1 /*
   2  * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "jvm.h"
  28 #include "cds/dynamicArchive.hpp"
  29 #include "cds/metaspaceShared.hpp"
  30 #include "classfile/classLoader.hpp"
  31 #include "classfile/javaClasses.hpp"
  32 #include "classfile/javaThreadStatus.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmClasses.hpp"
  35 #include "classfile/vmSymbols.hpp"
  36 #include "code/codeCache.hpp"
  37 #include "code/scopeDesc.hpp"
  38 #include "compiler/compileBroker.hpp"
  39 #include "compiler/compileTask.hpp"
  40 #include "compiler/compilerThread.hpp"
  41 #include "gc/shared/barrierSet.hpp"
  42 #include "gc/shared/collectedHeap.hpp"
  43 #include "gc/shared/gcId.hpp"
  44 #include "gc/shared/gcLocker.inline.hpp"
  45 #include "gc/shared/gcVMOperations.hpp"
  46 #include "gc/shared/oopStorage.hpp"
  47 #include "gc/shared/oopStorageSet.hpp"
  48 #include "gc/shared/stringdedup/stringDedup.hpp"
  49 #include "gc/shared/tlab_globals.hpp"
  50 #include "interpreter/interpreter.hpp"
  51 #include "interpreter/linkResolver.hpp"
  52 #include "interpreter/oopMapCache.hpp"
  53 #include "jfr/jfrEvents.hpp"
  54 #include "jvmtifiles/jvmtiEnv.hpp"
  55 #include "logging/log.hpp"
  56 #include "logging/logAsyncWriter.hpp"
  57 #include "logging/logConfiguration.hpp"
  58 #include "logging/logStream.hpp"
  59 #include "memory/allocation.inline.hpp"
  60 #include "memory/iterator.hpp"
  61 #include "memory/oopFactory.hpp"
  62 #include "memory/resourceArea.hpp"
  63 #include "memory/universe.hpp"
  64 #include "oops/access.inline.hpp"
  65 #include "oops/instanceKlass.hpp"
  66 #include "oops/klass.inline.hpp"
  67 #include "oops/objArrayOop.hpp"
  68 #include "oops/oop.inline.hpp"
  69 #include "oops/oopHandle.inline.hpp"
  70 #include "oops/symbol.hpp"
  71 #include "oops/typeArrayOop.inline.hpp"
  72 #include "oops/verifyOopClosure.hpp"
  73 #include "prims/jvm_misc.hpp"
  74 #include "prims/jvmtiDeferredUpdates.hpp"
  75 #include "prims/jvmtiExport.hpp"
  76 #include "prims/jvmtiThreadState.hpp"
  77 #include "runtime/arguments.hpp"
  78 #include "runtime/atomic.hpp"
  79 #include "runtime/fieldDescriptor.inline.hpp"
  80 #include "runtime/flags/jvmFlagLimit.hpp"
  81 #include "runtime/deoptimization.hpp"
  82 #include "runtime/frame.inline.hpp"
  83 #include "runtime/handles.inline.hpp"
  84 #include "runtime/handshake.hpp"
  85 #include "runtime/init.hpp"
  86 #include "runtime/interfaceSupport.inline.hpp"
  87 #include "runtime/java.hpp"
  88 #include "runtime/javaCalls.hpp"
  89 #include "runtime/jniHandles.inline.hpp"
  90 #include "runtime/jniPeriodicChecker.hpp"
  91 #include "runtime/monitorDeflationThread.hpp"
  92 #include "runtime/mutexLocker.hpp"
  93 #include "runtime/nonJavaThread.hpp"
  94 #include "runtime/objectMonitor.hpp"
  95 #include "runtime/orderAccess.hpp"
  96 #include "runtime/osThread.hpp"
  97 #include "runtime/safepoint.hpp"
  98 #include "runtime/safepointMechanism.inline.hpp"
  99 #include "runtime/safepointVerifiers.hpp"
 100 #include "runtime/serviceThread.hpp"
 101 #include "runtime/sharedRuntime.hpp"
 102 #include "runtime/stackFrameStream.inline.hpp"
 103 #include "runtime/stackWatermarkSet.hpp"
 104 #include "runtime/statSampler.hpp"
 105 #include "runtime/task.hpp"
 106 #include "runtime/thread.inline.hpp"
 107 #include "runtime/threadCritical.hpp"
 108 #include "runtime/threadSMR.inline.hpp"
 109 #include "runtime/threadStatisticalInfo.hpp"
 110 #include "runtime/threadWXSetters.inline.hpp"
 111 #include "runtime/timer.hpp"
 112 #include "runtime/timerTrace.hpp"
 113 #include "runtime/vframe.inline.hpp"
 114 #include "runtime/vframeArray.hpp"
 115 #include "runtime/vframe_hp.hpp"
 116 #include "runtime/vmThread.hpp"
 117 #include "runtime/vmOperations.hpp"
 118 #include "runtime/vm_version.hpp"
 119 #include "services/attachListener.hpp"
 120 #include "services/management.hpp"
 121 #include "services/memTracker.hpp"
 122 #include "services/threadService.hpp"
 123 #include "utilities/align.hpp"
 124 #include "utilities/copy.hpp"
 125 #include "utilities/defaultStream.hpp"
 126 #include "utilities/dtrace.hpp"
 127 #include "utilities/events.hpp"
 128 #include "utilities/macros.hpp"
 129 #include "utilities/preserveException.hpp"
 130 #include "utilities/spinYield.hpp"
 131 #include "utilities/vmError.hpp"
 132 #if INCLUDE_JVMCI
 133 #include "jvmci/jvmci.hpp"
 134 #include "jvmci/jvmciEnv.hpp"
 135 #endif
 136 #ifdef COMPILER1
 137 #include "c1/c1_Compiler.hpp"
 138 #endif
 139 #ifdef COMPILER2
 140 #include "opto/c2compiler.hpp"
 141 #include "opto/idealGraphPrinter.hpp"
 142 #endif
 143 #if INCLUDE_RTM_OPT
 144 #include "runtime/rtmLocking.hpp"
 145 #endif
 146 #if INCLUDE_JFR
 147 #include "jfr/jfr.hpp"
 148 #endif
 149 
 150 // Initialization after module runtime initialization
 151 void universe_post_module_init();  // must happen after call_initPhase2
 152 
 153 #ifdef DTRACE_ENABLED
 154 
 155 // Only bother with this argument setup if dtrace is available
 156 
 157   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 158   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 159 
 160   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 161     {                                                                      \
 162       ResourceMark rm(this);                                               \
 163       int len = 0;                                                         \
 164       const char* name = (javathread)->name();                             \
 165       len = strlen(name);                                                  \
 166       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 167         (char *) name, len,                                                \
 168         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 169         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 170         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 171     }
 172 
 173 #else //  ndef DTRACE_ENABLED
 174 
 175   #define DTRACE_THREAD_PROBE(probe, javathread)
 176 
 177 #endif // ndef DTRACE_ENABLED
 178 
 179 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 180 // Current thread is maintained as a thread-local variable
 181 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
 182 #endif
 183 
 184 // ======= Thread ========
 185 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 186   return throw_excpt ? AllocateHeap(size, flags, CURRENT_PC)
 187                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 188 }
 189 
 190 void Thread::operator delete(void* p) {
 191   FreeHeap(p);
 192 }
 193 
 194 void JavaThread::smr_delete() {
 195   if (_on_thread_list) {
 196     ThreadsSMRSupport::smr_delete(this);
 197   } else {
 198     delete this;
 199   }
 200 }
 201 
 202 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 203 // JavaThread
 204 
 205 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
 206 
 207 Thread::Thread() {
 208 
 209   DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
 210 
 211   // stack and get_thread
 212   set_stack_base(NULL);
 213   set_stack_size(0);
 214   set_lgrp_id(-1);
 215   DEBUG_ONLY(clear_suspendible_thread();)
 216 
 217   // allocated data structures
 218   set_osthread(NULL);
 219   set_resource_area(new (mtThread)ResourceArea());
 220   DEBUG_ONLY(_current_resource_mark = NULL;)
 221   set_handle_area(new (mtThread) HandleArea(NULL));
 222   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, mtClass));
 223   set_active_handles(NULL);
 224   set_free_handle_block(NULL);
 225   set_last_handle_mark(NULL);
 226   DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
 227 
 228   // Initial value of zero ==> never claimed.
 229   _threads_do_token = 0;
 230   _threads_hazard_ptr = NULL;
 231   _threads_list_ptr = NULL;
 232   _nested_threads_hazard_ptr_cnt = 0;
 233   _rcu_counter = 0;
 234 
 235   // the handle mark links itself to last_handle_mark
 236   new HandleMark(this);
 237 
 238   // plain initialization
 239   debug_only(_owned_locks = NULL;)
 240   NOT_PRODUCT(_skip_gcalot = false;)
 241   _jvmti_env_iteration_count = 0;
 242   set_allocated_bytes(0);
 243   _current_pending_raw_monitor = NULL;
 244 
 245   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 246   _hashStateX = os::random();
 247   _hashStateY = 842502087;
 248   _hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
 249   _hashStateW = 273326509;
 250 
 251   // Many of the following fields are effectively final - immutable
 252   // Note that nascent threads can't use the Native Monitor-Mutex
 253   // construct until the _MutexEvent is initialized ...
 254   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 255   // we might instead use a stack of ParkEvents that we could provision on-demand.
 256   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 257   // and ::Release()
 258   _ParkEvent   = ParkEvent::Allocate(this);
 259 
 260 #ifdef CHECK_UNHANDLED_OOPS
 261   if (CheckUnhandledOops) {
 262     _unhandled_oops = new UnhandledOops(this);
 263   }
 264 #endif // CHECK_UNHANDLED_OOPS
 265 
 266   // Notify the barrier set that a thread is being created. The initial
 267   // thread is created before the barrier set is available.  The call to
 268   // BarrierSet::on_thread_create() for this thread is therefore deferred
 269   // to BarrierSet::set_barrier_set().
 270   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 271   if (barrier_set != NULL) {
 272     barrier_set->on_thread_create(this);
 273   } else {
 274     // Only the main thread should be created before the barrier set
 275     // and that happens just before Thread::current is set. No other thread
 276     // can attach as the VM is not created yet, so they can't execute this code.
 277     // If the main thread creates other threads before the barrier set that is an error.
 278     assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
 279   }
 280 
 281   MACOS_AARCH64_ONLY(DEBUG_ONLY(_wx_init = false));
 282 }
 283 
 284 void Thread::initialize_tlab() {
 285   if (UseTLAB) {
 286     tlab().initialize();
 287   }
 288 }
 289 
 290 void Thread::initialize_thread_current() {
 291 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 292   assert(_thr_current == NULL, "Thread::current already initialized");
 293   _thr_current = this;
 294 #endif
 295   assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
 296   ThreadLocalStorage::set_thread(this);
 297   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 298 }
 299 
 300 void Thread::clear_thread_current() {
 301   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 302 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 303   _thr_current = NULL;
 304 #endif
 305   ThreadLocalStorage::set_thread(NULL);
 306 }
 307 
 308 void Thread::record_stack_base_and_size() {
 309   // Note: at this point, Thread object is not yet initialized. Do not rely on
 310   // any members being initialized. Do not rely on Thread::current() being set.
 311   // If possible, refrain from doing anything which may crash or assert since
 312   // quite probably those crash dumps will be useless.
 313   set_stack_base(os::current_stack_base());
 314   set_stack_size(os::current_stack_size());
 315 
 316   // Set stack limits after thread is initialized.
 317   if (is_Java_thread()) {
 318     JavaThread::cast(this)->stack_overflow_state()->initialize(stack_base(), stack_end());
 319   }
 320 }
 321 
 322 #if INCLUDE_NMT
 323 void Thread::register_thread_stack_with_NMT() {
 324   MemTracker::record_thread_stack(stack_end(), stack_size());
 325 }
 326 
 327 void Thread::unregister_thread_stack_with_NMT() {
 328   MemTracker::release_thread_stack(stack_end(), stack_size());
 329 }
 330 #endif // INCLUDE_NMT
 331 
 332 void Thread::call_run() {
 333   DEBUG_ONLY(_run_state = CALL_RUN;)
 334 
 335   // At this point, Thread object should be fully initialized and
 336   // Thread::current() should be set.
 337 
 338   assert(Thread::current_or_null() != NULL, "current thread is unset");
 339   assert(Thread::current_or_null() == this, "current thread is wrong");
 340 
 341   // Perform common initialization actions
 342 
 343   register_thread_stack_with_NMT();
 344 
 345   MACOS_AARCH64_ONLY(this->init_wx());
 346 
 347   JFR_ONLY(Jfr::on_thread_start(this);)
 348 
 349   log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
 350     PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
 351     os::current_thread_id(), p2i(stack_end()),
 352     p2i(stack_base()), stack_size()/1024);
 353 
 354   // Perform <ChildClass> initialization actions
 355   DEBUG_ONLY(_run_state = PRE_RUN;)
 356   this->pre_run();
 357 
 358   // Invoke <ChildClass>::run()
 359   DEBUG_ONLY(_run_state = RUN;)
 360   this->run();
 361   // Returned from <ChildClass>::run(). Thread finished.
 362 
 363   // Perform common tear-down actions
 364 
 365   assert(Thread::current_or_null() != NULL, "current thread is unset");
 366   assert(Thread::current_or_null() == this, "current thread is wrong");
 367 
 368   // Perform <ChildClass> tear-down actions
 369   DEBUG_ONLY(_run_state = POST_RUN;)
 370   this->post_run();
 371 
 372   // Note: at this point the thread object may already have deleted itself,
 373   // so from here on do not dereference *this*. Not all thread types currently
 374   // delete themselves when they terminate. But no thread should ever be deleted
 375   // asynchronously with respect to its termination - that is what _run_state can
 376   // be used to check.
 377 
 378   assert(Thread::current_or_null() == NULL, "current thread still present");
 379 }
 380 
 381 Thread::~Thread() {
 382 
 383   // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
 384   // get started due to errors etc. Any active thread should at least reach post_run
 385   // before it is deleted (usually in post_run()).
 386   assert(_run_state == PRE_CALL_RUN ||
 387          _run_state == POST_RUN, "Active Thread deleted before post_run(): "
 388          "_run_state=%d", (int)_run_state);
 389 
 390   // Notify the barrier set that a thread is being destroyed. Note that a barrier
 391   // set might not be available if we encountered errors during bootstrapping.
 392   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 393   if (barrier_set != NULL) {
 394     barrier_set->on_thread_destroy(this);
 395   }
 396 
 397   // deallocate data structures
 398   delete resource_area();
 399   // since the handle marks are using the handle area, we have to deallocated the root
 400   // handle mark before deallocating the thread's handle area,
 401   assert(last_handle_mark() != NULL, "check we have an element");
 402   delete last_handle_mark();
 403   assert(last_handle_mark() == NULL, "check we have reached the end");
 404 
 405   ParkEvent::Release(_ParkEvent);
 406   // Set to NULL as a termination indicator for has_terminated().
 407   Atomic::store(&_ParkEvent, (ParkEvent*)NULL);
 408 
 409   delete handle_area();
 410   delete metadata_handles();
 411 
 412   // osthread() can be NULL, if creation of thread failed.
 413   if (osthread() != NULL) os::free_thread(osthread());
 414 
 415   // Clear Thread::current if thread is deleting itself and it has not
 416   // already been done. This must be done before the memory is deallocated.
 417   // Needed to ensure JNI correctly detects non-attached threads.
 418   if (this == Thread::current_or_null()) {
 419     Thread::clear_thread_current();
 420   }
 421 
 422   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 423 }
 424 
 425 #ifdef ASSERT
 426 // A JavaThread is considered dangling if it not handshake-safe with respect to
 427 // the current thread, it is not on a ThreadsList, or not at safepoint.
 428 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
 429   assert(!thread->is_Java_thread() ||
 430          JavaThread::cast(thread)->is_handshake_safe_for(Thread::current()) ||
 431          !JavaThread::cast(thread)->on_thread_list() ||
 432          SafepointSynchronize::is_at_safepoint() ||
 433          ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread::cast(thread)),
 434          "possibility of dangling Thread pointer");
 435 }
 436 #endif
 437 
 438 // Is the target JavaThread protected by the calling Thread
 439 // or by some other mechanism:
 440 bool Thread::is_JavaThread_protected(const JavaThread* p) {
 441   // Do the simplest check first:
 442   if (SafepointSynchronize::is_at_safepoint()) {
 443     // The target is protected since JavaThreads cannot exit
 444     // while we're at a safepoint.
 445     return true;
 446   }
 447 
 448   // If the target hasn't been started yet then it is trivially
 449   // "protected". We assume the caller is the thread that will do
 450   // the starting.
 451   if (p->osthread() == NULL || p->osthread()->get_state() <= INITIALIZED) {
 452     return true;
 453   }
 454 
 455   // Now make the simple checks based on who the caller is:
 456   Thread* current_thread = Thread::current();
 457   if (current_thread == p || Threads_lock->owner() == current_thread) {
 458     // Target JavaThread is self or calling thread owns the Threads_lock.
 459     // Second check is the same as Threads_lock->owner_is_self(),
 460     // but we already have the current thread so check directly.
 461     return true;
 462   }
 463 
 464   // Check the ThreadsLists associated with the calling thread (if any)
 465   // to see if one of them protects the target JavaThread:
 466   for (SafeThreadsListPtr* stlp = current_thread->_threads_list_ptr;
 467        stlp != NULL; stlp = stlp->previous()) {
 468     if (stlp->list()->includes(p)) {
 469       // The target JavaThread is protected by this ThreadsList:
 470       return true;
 471     }
 472   }
 473 
 474   // Use this debug code with -XX:+UseNewCode to diagnose locations that
 475   // are missing a ThreadsListHandle or other protection mechanism:
 476   // guarantee(!UseNewCode, "current_thread=" INTPTR_FORMAT " is not protecting p="
 477   //           INTPTR_FORMAT, p2i(current_thread), p2i(p));
 478 
 479   // Note: Since 'p' isn't protected by a TLH, the call to
 480   // p->is_handshake_safe_for() may crash, but we have debug bits so
 481   // we'll be able to figure out what protection mechanism is missing.
 482   assert(p->is_handshake_safe_for(current_thread), "JavaThread=" INTPTR_FORMAT
 483          " is not protected and not handshake safe.", p2i(p));
 484 
 485   // The target JavaThread is not protected so it is not safe to query:
 486   return false;
 487 }
 488 
 489 ThreadPriority Thread::get_priority(const Thread* const thread) {
 490   ThreadPriority priority;
 491   // Can return an error!
 492   (void)os::get_priority(thread, priority);
 493   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 494   return priority;
 495 }
 496 
 497 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 498   debug_only(check_for_dangling_thread_pointer(thread);)
 499   // Can return an error!
 500   (void)os::set_priority(thread, priority);
 501 }
 502 
 503 
 504 void Thread::start(Thread* thread) {
 505   // Start is different from resume in that its safety is guaranteed by context or
 506   // being called from a Java method synchronized on the Thread object.
 507   if (thread->is_Java_thread()) {
 508     // Initialize the thread state to RUNNABLE before starting this thread.
 509     // Can not set it after the thread started because we do not know the
 510     // exact thread state at that time. It could be in MONITOR_WAIT or
 511     // in SLEEPING or some other state.
 512     java_lang_Thread::set_thread_status(JavaThread::cast(thread)->threadObj(),
 513                                         JavaThreadStatus::RUNNABLE);
 514   }
 515   os::start_thread(thread);
 516 }
 517 
 518 // GC Support
 519 bool Thread::claim_par_threads_do(uintx claim_token) {
 520   uintx token = _threads_do_token;
 521   if (token != claim_token) {
 522     uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
 523     if (res == token) {
 524       return true;
 525     }
 526     guarantee(res == claim_token, "invariant");
 527   }
 528   return false;
 529 }
 530 
 531 void Thread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
 532   if (active_handles() != NULL) {
 533     active_handles()->oops_do(f);
 534   }
 535   // Do oop for ThreadShadow
 536   f->do_oop((oop*)&_pending_exception);
 537   handle_area()->oops_do(f);
 538 }
 539 
 540 // If the caller is a NamedThread, then remember, in the current scope,
 541 // the given JavaThread in its _processed_thread field.
 542 class RememberProcessedThread: public StackObj {
 543   NamedThread* _cur_thr;
 544 public:
 545   RememberProcessedThread(Thread* thread) {
 546     Thread* self = Thread::current();
 547     if (self->is_Named_thread()) {
 548       _cur_thr = (NamedThread *)self;
 549       assert(_cur_thr->processed_thread() == NULL, "nesting not supported");
 550       _cur_thr->set_processed_thread(thread);
 551     } else {
 552       _cur_thr = NULL;
 553     }
 554   }
 555 
 556   ~RememberProcessedThread() {
 557     if (_cur_thr) {
 558       assert(_cur_thr->processed_thread() != NULL, "nesting not supported");
 559       _cur_thr->set_processed_thread(NULL);
 560     }
 561   }
 562 };
 563 
 564 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
 565   // Record JavaThread to GC thread
 566   RememberProcessedThread rpt(this);
 567   oops_do_no_frames(f, cf);
 568   oops_do_frames(f, cf);
 569 }
 570 
 571 void Thread::metadata_handles_do(void f(Metadata*)) {
 572   // Only walk the Handles in Thread.
 573   if (metadata_handles() != NULL) {
 574     for (int i = 0; i< metadata_handles()->length(); i++) {
 575       f(metadata_handles()->at(i));
 576     }
 577   }
 578 }
 579 
 580 void Thread::print_on(outputStream* st, bool print_extended_info) const {
 581   // get_priority assumes osthread initialized
 582   if (osthread() != NULL) {
 583     int os_prio;
 584     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 585       st->print("os_prio=%d ", os_prio);
 586     }
 587 
 588     st->print("cpu=%.2fms ",
 589               os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
 590               );
 591     st->print("elapsed=%.2fs ",
 592               _statistical_info.getElapsedTime() / 1000.0
 593               );
 594     if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
 595       size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
 596       st->print("allocated=" SIZE_FORMAT "%s ",
 597                 byte_size_in_proper_unit(allocated_bytes),
 598                 proper_unit_for_byte_size(allocated_bytes)
 599                 );
 600       st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
 601     }
 602 
 603     st->print("tid=" INTPTR_FORMAT " ", p2i(this));
 604     osthread()->print_on(st);
 605   }
 606   ThreadsSMRSupport::print_info_on(this, st);
 607   st->print(" ");
 608   debug_only(if (WizardMode) print_owned_locks_on(st);)
 609 }
 610 
 611 void Thread::print() const { print_on(tty); }
 612 
 613 // Thread::print_on_error() is called by fatal error handler. Don't use
 614 // any lock or allocate memory.
 615 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 616   assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
 617 
 618   st->print("%s \"%s\"", type_name(), name());
 619 
 620   OSThread* os_thr = osthread();
 621   if (os_thr != NULL) {
 622     if (os_thr->get_state() != ZOMBIE) {
 623       st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 624                 p2i(stack_end()), p2i(stack_base()));
 625       st->print(" [id=%d]", osthread()->thread_id());
 626     } else {
 627       st->print(" terminated");
 628     }
 629   } else {
 630     st->print(" unknown state (no osThread)");
 631   }
 632   ThreadsSMRSupport::print_info_on(this, st);
 633 }
 634 
 635 void Thread::print_value_on(outputStream* st) const {
 636   if (is_Named_thread()) {
 637     st->print(" \"%s\" ", name());
 638   }
 639   st->print(INTPTR_FORMAT, p2i(this));   // print address
 640 }
 641 
 642 #ifdef ASSERT
 643 void Thread::print_owned_locks_on(outputStream* st) const {
 644   Mutex* cur = _owned_locks;
 645   if (cur == NULL) {
 646     st->print(" (no locks) ");
 647   } else {
 648     st->print_cr(" Locks owned:");
 649     while (cur) {
 650       cur->print_on(st);
 651       cur = cur->next();
 652     }
 653   }
 654 }
 655 #endif // ASSERT
 656 
 657 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 658 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 659 // used for compilation in the future. If that change is made, the need for these methods
 660 // should be revisited, and they should be removed if possible.
 661 
 662 bool Thread::is_lock_owned(address adr) const {
 663   return is_in_full_stack(adr);
 664 }
 665 
 666 bool Thread::set_as_starting_thread() {
 667   assert(_starting_thread == NULL, "already initialized: "
 668          "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
 669   // NOTE: this must be called inside the main thread.
 670   DEBUG_ONLY(_starting_thread = this;)
 671   return os::create_main_thread(JavaThread::cast(this));
 672 }
 673 
 674 static void initialize_class(Symbol* class_name, TRAPS) {
 675   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 676   InstanceKlass::cast(klass)->initialize(CHECK);
 677 }
 678 
 679 
 680 // Creates the initial ThreadGroup
 681 static Handle create_initial_thread_group(TRAPS) {
 682   Handle system_instance = JavaCalls::construct_new_instance(
 683                             vmClasses::ThreadGroup_klass(),
 684                             vmSymbols::void_method_signature(),
 685                             CHECK_NH);
 686   Universe::set_system_thread_group(system_instance());
 687 
 688   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 689   Handle main_instance = JavaCalls::construct_new_instance(
 690                             vmClasses::ThreadGroup_klass(),
 691                             vmSymbols::threadgroup_string_void_signature(),
 692                             system_instance,
 693                             string,
 694                             CHECK_NH);
 695   return main_instance;
 696 }
 697 
 698 // Creates the initial Thread, and sets it to running.
 699 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 700                                  TRAPS) {
 701   InstanceKlass* ik = vmClasses::Thread_klass();
 702   assert(ik->is_initialized(), "must be");
 703   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 704 
 705   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 706   // constructor calls Thread.current(), which must be set here for the
 707   // initial thread.
 708   java_lang_Thread::set_thread(thread_oop(), thread);
 709   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 710   thread->set_threadObj(thread_oop());
 711 
 712   Handle string = java_lang_String::create_from_str("main", CHECK);
 713 
 714   JavaValue result(T_VOID);
 715   JavaCalls::call_special(&result, thread_oop,
 716                           ik,
 717                           vmSymbols::object_initializer_name(),
 718                           vmSymbols::threadgroup_string_void_signature(),
 719                           thread_group,
 720                           string,
 721                           CHECK);
 722 
 723   // Set thread status to running since main thread has
 724   // been started and running.
 725   java_lang_Thread::set_thread_status(thread_oop(),
 726                                       JavaThreadStatus::RUNNABLE);
 727 }
 728 
 729 // Extract version and vendor specific information from
 730 // java.lang.VersionProps fields.
 731 // Returned char* is allocated in the thread's resource area
 732 // so must be copied for permanency.
 733 static const char* get_java_version_info(InstanceKlass* ik,
 734                                          Symbol* field_name) {
 735   fieldDescriptor fd;
 736   bool found = ik != NULL &&
 737                ik->find_local_field(field_name,
 738                                     vmSymbols::string_signature(), &fd);
 739   if (found) {
 740     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 741     if (name_oop == NULL) {
 742       return NULL;
 743     }
 744     const char* name = java_lang_String::as_utf8_string(name_oop);
 745     return name;
 746   } else {
 747     return NULL;
 748   }
 749 }
 750 
 751 // General purpose hook into Java code, run once when the VM is initialized.
 752 // The Java library method itself may be changed independently from the VM.
 753 static void call_postVMInitHook(TRAPS) {
 754   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 755   if (klass != NULL) {
 756     JavaValue result(T_VOID);
 757     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 758                            vmSymbols::void_method_signature(),
 759                            CHECK);
 760   }
 761 }
 762 
 763 // Initialized by VMThread at vm_global_init
 764 static OopStorage* _thread_oop_storage = NULL;
 765 
 766 oop  JavaThread::threadObj() const    {
 767   return _threadObj.resolve();
 768 }
 769 
 770 void JavaThread::set_threadObj(oop p) {
 771   assert(_thread_oop_storage != NULL, "not yet initialized");
 772   _threadObj = OopHandle(_thread_oop_storage, p);
 773 }
 774 
 775 OopStorage* JavaThread::thread_oop_storage() {
 776   assert(_thread_oop_storage != NULL, "not yet initialized");
 777   return _thread_oop_storage;
 778 }
 779 
 780 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
 781                                     bool daemon, TRAPS) {
 782   assert(thread_group.not_null(), "thread group should be specified");
 783   assert(threadObj() == NULL, "should only create Java thread object once");
 784 
 785   InstanceKlass* ik = vmClasses::Thread_klass();
 786   assert(ik->is_initialized(), "must be");
 787   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 788 
 789   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
 790   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 791   // constructor calls Thread.current(), which must be set here.
 792   java_lang_Thread::set_thread(thread_oop(), this);
 793   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 794   set_threadObj(thread_oop());
 795 
 796   JavaValue result(T_VOID);
 797   if (thread_name != NULL) {
 798     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 799     // Thread gets assigned specified name and null target
 800     JavaCalls::call_special(&result,
 801                             thread_oop,
 802                             ik,
 803                             vmSymbols::object_initializer_name(),
 804                             vmSymbols::threadgroup_string_void_signature(),
 805                             thread_group,
 806                             name,
 807                             THREAD);
 808   } else {
 809     // Thread gets assigned name "Thread-nnn" and null target
 810     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 811     JavaCalls::call_special(&result,
 812                             thread_oop,
 813                             ik,
 814                             vmSymbols::object_initializer_name(),
 815                             vmSymbols::threadgroup_runnable_void_signature(),
 816                             thread_group,
 817                             Handle(),
 818                             THREAD);
 819   }
 820 
 821 
 822   if (daemon) {
 823     java_lang_Thread::set_daemon(thread_oop());
 824   }
 825 
 826   if (HAS_PENDING_EXCEPTION) {
 827     return;
 828   }
 829 
 830   Klass* group = vmClasses::ThreadGroup_klass();
 831   Handle threadObj(THREAD, this->threadObj());
 832 
 833   JavaCalls::call_special(&result,
 834                           thread_group,
 835                           group,
 836                           vmSymbols::add_method_name(),
 837                           vmSymbols::thread_void_signature(),
 838                           threadObj,          // Arg 1
 839                           THREAD);
 840 }
 841 
 842 // ======= JavaThread ========
 843 
 844 #if INCLUDE_JVMCI
 845 
 846 jlong* JavaThread::_jvmci_old_thread_counters;
 847 
 848 bool jvmci_counters_include(JavaThread* thread) {
 849   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 850 }
 851 
 852 void JavaThread::collect_counters(jlong* array, int length) {
 853   assert(length == JVMCICounterSize, "wrong value");
 854   for (int i = 0; i < length; i++) {
 855     array[i] = _jvmci_old_thread_counters[i];
 856   }
 857   for (JavaThread* tp : ThreadsListHandle()) {
 858     if (jvmci_counters_include(tp)) {
 859       for (int i = 0; i < length; i++) {
 860         array[i] += tp->_jvmci_counters[i];
 861       }
 862     }
 863   }
 864 }
 865 
 866 // Attempt to enlarge the array for per thread counters.
 867 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 868   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 869   if (new_counters == NULL) {
 870     return NULL;
 871   }
 872   if (old_counters == NULL) {
 873     old_counters = new_counters;
 874     memset(old_counters, 0, sizeof(jlong) * new_size);
 875   } else {
 876     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 877       new_counters[i] = old_counters[i];
 878     }
 879     if (new_size > current_size) {
 880       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 881     }
 882     FREE_C_HEAP_ARRAY(jlong, old_counters);
 883   }
 884   return new_counters;
 885 }
 886 
 887 // Attempt to enlarge the array for per thread counters.
 888 bool JavaThread::resize_counters(int current_size, int new_size) {
 889   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 890   if (new_counters == NULL) {
 891     return false;
 892   } else {
 893     _jvmci_counters = new_counters;
 894     return true;
 895   }
 896 }
 897 
 898 class VM_JVMCIResizeCounters : public VM_Operation {
 899  private:
 900   int _new_size;
 901   bool _failed;
 902 
 903  public:
 904   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 905   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 906   bool allow_nested_vm_operations() const        { return true; }
 907   void doit() {
 908     // Resize the old thread counters array
 909     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 910     if (new_counters == NULL) {
 911       _failed = true;
 912       return;
 913     } else {
 914       JavaThread::_jvmci_old_thread_counters = new_counters;
 915     }
 916 
 917     // Now resize each threads array
 918     for (JavaThread* tp : ThreadsListHandle()) {
 919       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 920         _failed = true;
 921         break;
 922       }
 923     }
 924     if (!_failed) {
 925       JVMCICounterSize = _new_size;
 926     }
 927   }
 928 
 929   bool failed() { return _failed; }
 930 };
 931 
 932 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 933   VM_JVMCIResizeCounters op(new_size);
 934   VMThread::execute(&op);
 935   return !op.failed();
 936 }
 937 
 938 #endif // INCLUDE_JVMCI
 939 
 940 #ifdef ASSERT
 941 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 942 void JavaThread::check_possible_safepoint() {
 943   if (_no_safepoint_count > 0) {
 944     print_owned_locks();
 945     assert(false, "Possible safepoint reached by thread that does not allow it");
 946   }
 947 #ifdef CHECK_UNHANDLED_OOPS
 948   // Clear unhandled oops in JavaThreads so we get a crash right away.
 949   clear_unhandled_oops();
 950 #endif // CHECK_UNHANDLED_OOPS
 951 
 952   // Macos/aarch64 should be in the right state for safepoint (e.g.
 953   // deoptimization needs WXWrite).  Crashes caused by the wrong state rarely
 954   // happens in practice, making such issues hard to find and reproduce.
 955 #if defined(__APPLE__) && defined(AARCH64)
 956   if (AssertWXAtThreadSync) {
 957     assert_wx_state(WXWrite);
 958   }
 959 #endif
 960 }
 961 
 962 void JavaThread::check_for_valid_safepoint_state() {
 963   // Check NoSafepointVerifier, which is implied by locks taken that can be
 964   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
 965   // are held.
 966   check_possible_safepoint();
 967 
 968   if (thread_state() != _thread_in_vm) {
 969     fatal("LEAF method calling lock?");
 970   }
 971 
 972   if (GCALotAtAllSafepoints) {
 973     // We could enter a safepoint here and thus have a gc
 974     InterfaceSupport::check_gc_alot();
 975   }
 976 }
 977 #endif // ASSERT
 978 
 979 // A JavaThread is a normal Java thread
 980 
 981 JavaThread::JavaThread() :
 982   // Initialize fields
 983 
 984   _on_thread_list(false),
 985   DEBUG_ONLY(_java_call_counter(0) COMMA)
 986   _entry_point(nullptr),
 987   _deopt_mark(nullptr),
 988   _deopt_nmethod(nullptr),
 989   _vframe_array_head(nullptr),
 990   _vframe_array_last(nullptr),
 991   _jvmti_deferred_updates(nullptr),
 992   _callee_target(nullptr),
 993   _vm_result(nullptr),
 994   _vm_result_2(nullptr),
 995 
 996   _current_pending_monitor(NULL),
 997   _current_pending_monitor_is_from_java(true),
 998   _current_waiting_monitor(NULL),
 999   _Stalled(0),
1000 
1001   _monitor_chunks(nullptr),
1002 
1003   _suspend_flags(0),
1004   _async_exception_condition(_no_async_condition),
1005   _pending_async_exception(nullptr),
1006 
1007   _thread_state(_thread_new),
1008   _saved_exception_pc(nullptr),
1009 #ifdef ASSERT
1010   _no_safepoint_count(0),
1011   _visited_for_critical_count(false),
1012 #endif
1013 
1014   _terminated(_not_terminated),
1015   _in_deopt_handler(0),
1016   _doing_unsafe_access(false),
1017   _do_not_unlock_if_synchronized(false),
1018   _jni_attach_state(_not_attaching_via_jni),
1019 #if INCLUDE_JVMCI
1020   _pending_deoptimization(-1),
1021   _pending_monitorenter(false),
1022   _pending_transfer_to_interpreter(false),
1023   _in_retryable_allocation(false),
1024   _pending_failed_speculation(0),
1025   _jvmci{nullptr},
1026   _jvmci_counters(nullptr),
1027   _jvmci_reserved0(0),
1028   _jvmci_reserved1(0),
1029   _jvmci_reserved_oop0(nullptr),
1030 #endif // INCLUDE_JVMCI
1031 
1032   _exception_oop(oop()),
1033   _exception_pc(0),
1034   _exception_handler_pc(0),
1035   _is_method_handle_return(0),
1036 
1037   _jni_active_critical(0),
1038   _pending_jni_exception_check_fn(nullptr),
1039   _depth_first_number(0),
1040 
1041   // JVMTI PopFrame support
1042   _popframe_condition(popframe_inactive),
1043   _frames_to_pop_failed_realloc(0),
1044 
1045   _handshake(this),
1046 
1047   _popframe_preserved_args(nullptr),
1048   _popframe_preserved_args_size(0),
1049 
1050   _jvmti_thread_state(nullptr),
1051   _interp_only_mode(0),
1052   _should_post_on_exceptions_flag(JNI_FALSE),
1053   _thread_stat(new ThreadStatistics()),
1054 
1055   _parker(),
1056 
1057   _class_to_be_initialized(nullptr),
1058 
1059   _SleepEvent(ParkEvent::Allocate(this))
1060 {
1061   set_jni_functions(jni_functions());
1062 
1063 #if INCLUDE_JVMCI
1064   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
1065   if (JVMCICounterSize > 0) {
1066     resize_counters(0, (int) JVMCICounterSize);
1067   }
1068 #endif // INCLUDE_JVMCI
1069 
1070   // Setup safepoint state info for this thread
1071   ThreadSafepointState::create(this);
1072 
1073   SafepointMechanism::initialize_header(this);
1074 
1075   set_requires_cross_modify_fence(false);
1076 
1077   pd_initialize();
1078   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1079 }
1080 
1081 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
1082   if (is_attaching_via_jni) {
1083     _jni_attach_state = _attaching_via_jni;
1084   }
1085 }
1086 
1087 
1088 // interrupt support
1089 
1090 void JavaThread::interrupt() {
1091   // All callers should have 'this' thread protected by a
1092   // ThreadsListHandle so that it cannot terminate and deallocate
1093   // itself.
1094   debug_only(check_for_dangling_thread_pointer(this);)
1095 
1096   // For Windows _interrupt_event
1097   osthread()->set_interrupted(true);
1098 
1099   // For Thread.sleep
1100   _SleepEvent->unpark();
1101 
1102   // For JSR166 LockSupport.park
1103   parker()->unpark();
1104 
1105   // For ObjectMonitor and JvmtiRawMonitor
1106   _ParkEvent->unpark();
1107 }
1108 
1109 
1110 bool JavaThread::is_interrupted(bool clear_interrupted) {
1111   debug_only(check_for_dangling_thread_pointer(this);)
1112 
1113   if (_threadObj.peek() == NULL) {
1114     // If there is no j.l.Thread then it is impossible to have
1115     // been interrupted. We can find NULL during VM initialization
1116     // or when a JNI thread is still in the process of attaching.
1117     // In such cases this must be the current thread.
1118     assert(this == Thread::current(), "invariant");
1119     return false;
1120   }
1121 
1122   bool interrupted = java_lang_Thread::interrupted(threadObj());
1123 
1124   // NOTE that since there is no "lock" around the interrupt and
1125   // is_interrupted operations, there is the possibility that the
1126   // interrupted flag will be "false" but that the
1127   // low-level events will be in the signaled state. This is
1128   // intentional. The effect of this is that Object.wait() and
1129   // LockSupport.park() will appear to have a spurious wakeup, which
1130   // is allowed and not harmful, and the possibility is so rare that
1131   // it is not worth the added complexity to add yet another lock.
1132   // For the sleep event an explicit reset is performed on entry
1133   // to JavaThread::sleep, so there is no early return. It has also been
1134   // recommended not to put the interrupted flag into the "event"
1135   // structure because it hides the issue.
1136   // Also, because there is no lock, we must only clear the interrupt
1137   // state if we are going to report that we were interrupted; otherwise
1138   // an interrupt that happens just after we read the field would be lost.
1139   if (interrupted && clear_interrupted) {
1140     assert(this == Thread::current(), "only the current thread can clear");
1141     java_lang_Thread::set_interrupted(threadObj(), false);
1142     osthread()->set_interrupted(false);
1143   }
1144 
1145   return interrupted;
1146 }
1147 
1148 void JavaThread::block_if_vm_exited() {
1149   if (_terminated == _vm_exited) {
1150     // _vm_exited is set at safepoint, and Threads_lock is never released
1151     // we will block here forever.
1152     // Here we can be doing a jump from a safe state to an unsafe state without
1153     // proper transition, but it happens after the final safepoint has begun.
1154     set_thread_state(_thread_in_vm);
1155     Threads_lock->lock();
1156     ShouldNotReachHere();
1157   }
1158 }
1159 
1160 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
1161   _jni_attach_state = _not_attaching_via_jni;
1162   set_entry_point(entry_point);
1163   // Create the native thread itself.
1164   // %note runtime_23
1165   os::ThreadType thr_type = os::java_thread;
1166   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
1167                                                             os::java_thread;
1168   os::create_thread(this, thr_type, stack_sz);
1169   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1170   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1171   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1172   // the exception consists of creating the exception object & initializing it, initialization
1173   // will leave the VM via a JavaCall and then all locks must be unlocked).
1174   //
1175   // The thread is still suspended when we reach here. Thread must be explicit started
1176   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1177   // by calling Threads:add. The reason why this is not done here, is because the thread
1178   // object must be fully initialized (take a look at JVM_Start)
1179 }
1180 
1181 JavaThread::~JavaThread() {
1182 
1183   // Ask ServiceThread to release the threadObj OopHandle
1184   ServiceThread::add_oop_handle_release(_threadObj);
1185 
1186   // Return the sleep event to the free list
1187   ParkEvent::Release(_SleepEvent);
1188   _SleepEvent = NULL;
1189 
1190   // Free any remaining  previous UnrollBlock
1191   vframeArray* old_array = vframe_array_last();
1192 
1193   if (old_array != NULL) {
1194     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1195     old_array->set_unroll_block(NULL);
1196     delete old_info;
1197     delete old_array;
1198   }
1199 
1200   JvmtiDeferredUpdates* updates = deferred_updates();
1201   if (updates != NULL) {
1202     // This can only happen if thread is destroyed before deoptimization occurs.
1203     assert(updates->count() > 0, "Updates holder not deleted");
1204     // free deferred updates.
1205     delete updates;
1206     set_deferred_updates(NULL);
1207   }
1208 
1209   // All Java related clean up happens in exit
1210   ThreadSafepointState::destroy(this);
1211   if (_thread_stat != NULL) delete _thread_stat;
1212 
1213 #if INCLUDE_JVMCI
1214   if (JVMCICounterSize > 0) {
1215     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1216   }
1217 #endif // INCLUDE_JVMCI
1218 }
1219 
1220 
1221 // First JavaThread specific code executed by a new Java thread.
1222 void JavaThread::pre_run() {
1223   // empty - see comments in run()
1224 }
1225 
1226 // The main routine called by a new Java thread. This isn't overridden
1227 // by subclasses, instead different subclasses define a different "entry_point"
1228 // which defines the actual logic for that kind of thread.
1229 void JavaThread::run() {
1230   // initialize thread-local alloc buffer related fields
1231   initialize_tlab();
1232 
1233   _stack_overflow_state.create_stack_guard_pages();
1234 
1235   cache_global_variables();
1236 
1237   // Thread is now sufficiently initialized to be handled by the safepoint code as being
1238   // in the VM. Change thread state from _thread_new to _thread_in_vm
1239   assert(this->thread_state() == _thread_new, "wrong thread state");
1240   set_thread_state(_thread_in_vm);
1241 
1242   // Before a thread is on the threads list it is always safe, so after leaving the
1243   // _thread_new we should emit a instruction barrier. The distance to modified code
1244   // from here is probably far enough, but this is consistent and safe.
1245   OrderAccess::cross_modify_fence();
1246 
1247   assert(JavaThread::current() == this, "sanity check");
1248   assert(!Thread::current()->owns_locks(), "sanity check");
1249 
1250   DTRACE_THREAD_PROBE(start, this);
1251 
1252   // This operation might block. We call that after all safepoint checks for a new thread has
1253   // been completed.
1254   set_active_handles(JNIHandleBlock::allocate_block());
1255 
1256   if (JvmtiExport::should_post_thread_life()) {
1257     JvmtiExport::post_thread_start(this);
1258 
1259   }
1260 
1261   // We call another function to do the rest so we are sure that the stack addresses used
1262   // from there will be lower than the stack base just computed.
1263   thread_main_inner();
1264 }
1265 
1266 void JavaThread::thread_main_inner() {
1267   assert(JavaThread::current() == this, "sanity check");
1268   assert(_threadObj.peek() != NULL, "just checking");
1269 
1270   // Execute thread entry point unless this thread has a pending exception
1271   // or has been stopped before starting.
1272   // Note: Due to JVM_StopThread we can have pending exceptions already!
1273   if (!this->has_pending_exception() &&
1274       !java_lang_Thread::is_stillborn(this->threadObj())) {
1275     {
1276       ResourceMark rm(this);
1277       this->set_native_thread_name(this->name());
1278     }
1279     HandleMark hm(this);
1280     this->entry_point()(this, this);
1281   }
1282 
1283   DTRACE_THREAD_PROBE(stop, this);
1284 
1285   // Cleanup is handled in post_run()
1286 }
1287 
1288 // Shared teardown for all JavaThreads
1289 void JavaThread::post_run() {
1290   this->exit(false);
1291   this->unregister_thread_stack_with_NMT();
1292   // Defer deletion to here to ensure 'this' is still referenceable in call_run
1293   // for any shared tear-down.
1294   this->smr_delete();
1295 }
1296 
1297 static void ensure_join(JavaThread* thread) {
1298   // We do not need to grab the Threads_lock, since we are operating on ourself.
1299   Handle threadObj(thread, thread->threadObj());
1300   assert(threadObj.not_null(), "java thread object must exist");
1301   ObjectLocker lock(threadObj, thread);
1302   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1303   thread->clear_pending_exception();
1304   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1305   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
1306   // Clear the native thread instance - this makes isAlive return false and allows the join()
1307   // to complete once we've done the notify_all below
1308   java_lang_Thread::set_thread(threadObj(), NULL);
1309   lock.notify_all(thread);
1310   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1311   thread->clear_pending_exception();
1312 }
1313 
1314 static bool is_daemon(oop threadObj) {
1315   return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1316 }
1317 
1318 // For any new cleanup additions, please check to see if they need to be applied to
1319 // cleanup_failed_attach_current_thread as well.
1320 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1321   assert(this == JavaThread::current(), "thread consistency check");
1322 
1323   elapsedTimer _timer_exit_phase1;
1324   elapsedTimer _timer_exit_phase2;
1325   elapsedTimer _timer_exit_phase3;
1326   elapsedTimer _timer_exit_phase4;
1327 
1328   if (log_is_enabled(Debug, os, thread, timer)) {
1329     _timer_exit_phase1.start();
1330   }
1331 
1332   HandleMark hm(this);
1333   Handle uncaught_exception(this, this->pending_exception());
1334   this->clear_pending_exception();
1335   Handle threadObj(this, this->threadObj());
1336   assert(threadObj.not_null(), "Java thread object should be created");
1337 
1338   if (!destroy_vm) {
1339     if (uncaught_exception.not_null()) {
1340       EXCEPTION_MARK;
1341       // Call method Thread.dispatchUncaughtException().
1342       Klass* thread_klass = vmClasses::Thread_klass();
1343       JavaValue result(T_VOID);
1344       JavaCalls::call_virtual(&result,
1345                               threadObj, thread_klass,
1346                               vmSymbols::dispatchUncaughtException_name(),
1347                               vmSymbols::throwable_void_signature(),
1348                               uncaught_exception,
1349                               THREAD);
1350       if (HAS_PENDING_EXCEPTION) {
1351         ResourceMark rm(this);
1352         jio_fprintf(defaultStream::error_stream(),
1353                     "\nException: %s thrown from the UncaughtExceptionHandler"
1354                     " in thread \"%s\"\n",
1355                     pending_exception()->klass()->external_name(),
1356                     name());
1357         CLEAR_PENDING_EXCEPTION;
1358       }
1359     }
1360 
1361     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1362     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1363     // is deprecated anyhow.
1364     if (!is_Compiler_thread()) {
1365       int count = 3;
1366       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1367         EXCEPTION_MARK;
1368         JavaValue result(T_VOID);
1369         Klass* thread_klass = vmClasses::Thread_klass();
1370         JavaCalls::call_virtual(&result,
1371                                 threadObj, thread_klass,
1372                                 vmSymbols::exit_method_name(),
1373                                 vmSymbols::void_method_signature(),
1374                                 THREAD);
1375         CLEAR_PENDING_EXCEPTION;
1376       }
1377     }
1378     // notify JVMTI
1379     if (JvmtiExport::should_post_thread_life()) {
1380       JvmtiExport::post_thread_end(this);
1381     }
1382 
1383     // The careful dance between thread suspension and exit is handled here.
1384     // Since we are in thread_in_vm state and suspension is done with handshakes,
1385     // we can just put in the exiting state and it will be correctly handled.
1386     set_terminated(_thread_exiting);
1387 
1388     ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1389   } else {
1390     assert(!is_terminated() && !is_exiting(), "must not be exiting");
1391     // before_exit() has already posted JVMTI THREAD_END events
1392   }
1393 
1394   if (log_is_enabled(Debug, os, thread, timer)) {
1395     _timer_exit_phase1.stop();
1396     _timer_exit_phase2.start();
1397   }
1398 
1399   // Capture daemon status before the thread is marked as terminated.
1400   bool daemon = is_daemon(threadObj());
1401 
1402   // Notify waiters on thread object. This has to be done after exit() is called
1403   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1404   // group should have the destroyed bit set before waiters are notified).
1405   ensure_join(this);
1406   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1407 
1408   if (log_is_enabled(Debug, os, thread, timer)) {
1409     _timer_exit_phase2.stop();
1410     _timer_exit_phase3.start();
1411   }
1412   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1413   // held by this thread must be released. The spec does not distinguish
1414   // between JNI-acquired and regular Java monitors. We can only see
1415   // regular Java monitors here if monitor enter-exit matching is broken.
1416   //
1417   // ensure_join() ignores IllegalThreadStateExceptions, and so does
1418   // ObjectSynchronizer::release_monitors_owned_by_thread().
1419   if (exit_type == jni_detach) {
1420     // Sanity check even though JNI DetachCurrentThread() would have
1421     // returned JNI_ERR if there was a Java frame. JavaThread exit
1422     // should be done executing Java code by the time we get here.
1423     assert(!this->has_last_Java_frame(),
1424            "should not have a Java frame when detaching or exiting");
1425     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1426     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1427   }
1428 
1429   // These things needs to be done while we are still a Java Thread. Make sure that thread
1430   // is in a consistent state, in case GC happens
1431   JFR_ONLY(Jfr::on_thread_exit(this);)
1432 
1433   if (active_handles() != NULL) {
1434     JNIHandleBlock* block = active_handles();
1435     set_active_handles(NULL);
1436     JNIHandleBlock::release_block(block);
1437   }
1438 
1439   if (free_handle_block() != NULL) {
1440     JNIHandleBlock* block = free_handle_block();
1441     set_free_handle_block(NULL);
1442     JNIHandleBlock::release_block(block);
1443   }
1444 
1445   // These have to be removed while this is still a valid thread.
1446   _stack_overflow_state.remove_stack_guard_pages();
1447 
1448   if (UseTLAB) {
1449     tlab().retire();
1450   }
1451 
1452   if (JvmtiEnv::environments_might_exist()) {
1453     JvmtiExport::cleanup_thread(this);
1454   }
1455 
1456   // We need to cache the thread name for logging purposes below as once
1457   // we have called on_thread_detach this thread must not access any oops.
1458   char* thread_name = NULL;
1459   if (log_is_enabled(Debug, os, thread, timer)) {
1460     ResourceMark rm(this);
1461     thread_name = os::strdup(name());
1462   }
1463 
1464   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
1465     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
1466     os::current_thread_id());
1467 
1468   if (log_is_enabled(Debug, os, thread, timer)) {
1469     _timer_exit_phase3.stop();
1470     _timer_exit_phase4.start();
1471   }
1472 
1473 #if INCLUDE_JVMCI
1474   if (JVMCICounterSize > 0) {
1475     if (jvmci_counters_include(this)) {
1476       for (int i = 0; i < JVMCICounterSize; i++) {
1477         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1478       }
1479     }
1480   }
1481 #endif // INCLUDE_JVMCI
1482 
1483   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1484   Threads::remove(this, daemon);
1485 
1486   if (log_is_enabled(Debug, os, thread, timer)) {
1487     _timer_exit_phase4.stop();
1488     log_debug(os, thread, timer)("name='%s'"
1489                                  ", exit-phase1=" JLONG_FORMAT
1490                                  ", exit-phase2=" JLONG_FORMAT
1491                                  ", exit-phase3=" JLONG_FORMAT
1492                                  ", exit-phase4=" JLONG_FORMAT,
1493                                  thread_name,
1494                                  _timer_exit_phase1.milliseconds(),
1495                                  _timer_exit_phase2.milliseconds(),
1496                                  _timer_exit_phase3.milliseconds(),
1497                                  _timer_exit_phase4.milliseconds());
1498     os::free(thread_name);
1499   }
1500 }
1501 
1502 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1503   if (active_handles() != NULL) {
1504     JNIHandleBlock* block = active_handles();
1505     set_active_handles(NULL);
1506     JNIHandleBlock::release_block(block);
1507   }
1508 
1509   if (free_handle_block() != NULL) {
1510     JNIHandleBlock* block = free_handle_block();
1511     set_free_handle_block(NULL);
1512     JNIHandleBlock::release_block(block);
1513   }
1514 
1515   // These have to be removed while this is still a valid thread.
1516   _stack_overflow_state.remove_stack_guard_pages();
1517 
1518   if (UseTLAB) {
1519     tlab().retire();
1520   }
1521 
1522   Threads::remove(this, is_daemon);
1523   this->smr_delete();
1524 }
1525 
1526 JavaThread* JavaThread::active() {
1527   Thread* thread = Thread::current();
1528   if (thread->is_Java_thread()) {
1529     return JavaThread::cast(thread);
1530   } else {
1531     assert(thread->is_VM_thread(), "this must be a vm thread");
1532     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1533     JavaThread *ret = op == NULL ? NULL : JavaThread::cast(op->calling_thread());
1534     return ret;
1535   }
1536 }
1537 
1538 bool JavaThread::is_lock_owned(address adr) const {
1539   if (Thread::is_lock_owned(adr)) return true;
1540 
1541   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1542     if (chunk->contains(adr)) return true;
1543   }
1544 
1545   return false;
1546 }
1547 
1548 oop JavaThread::exception_oop() const {
1549   return Atomic::load(&_exception_oop);
1550 }
1551 
1552 void JavaThread::set_exception_oop(oop o) {
1553   Atomic::store(&_exception_oop, o);
1554 }
1555 
1556 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1557   chunk->set_next(monitor_chunks());
1558   set_monitor_chunks(chunk);
1559 }
1560 
1561 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1562   guarantee(monitor_chunks() != NULL, "must be non empty");
1563   if (monitor_chunks() == chunk) {
1564     set_monitor_chunks(chunk->next());
1565   } else {
1566     MonitorChunk* prev = monitor_chunks();
1567     while (prev->next() != chunk) prev = prev->next();
1568     prev->set_next(chunk->next());
1569   }
1570 }
1571 
1572 
1573 // Asynchronous exceptions support
1574 //
1575 // Note: this function shouldn't block if it's called in
1576 // _thread_in_native_trans state (such as from
1577 // check_special_condition_for_native_trans()).
1578 void JavaThread::check_and_handle_async_exceptions() {
1579   if (has_last_Java_frame() && has_async_exception_condition()) {
1580     // If we are at a polling page safepoint (not a poll return)
1581     // then we must defer async exception because live registers
1582     // will be clobbered by the exception path. Poll return is
1583     // ok because the call we a returning from already collides
1584     // with exception handling registers and so there is no issue.
1585     // (The exception handling path kills call result registers but
1586     //  this is ok since the exception kills the result anyway).
1587 
1588     if (is_at_poll_safepoint()) {
1589       // if the code we are returning to has deoptimized we must defer
1590       // the exception otherwise live registers get clobbered on the
1591       // exception path before deoptimization is able to retrieve them.
1592       //
1593       RegisterMap map(this, false);
1594       frame caller_fr = last_frame().sender(&map);
1595       assert(caller_fr.is_compiled_frame(), "what?");
1596       if (caller_fr.is_deoptimized_frame()) {
1597         log_info(exceptions)("deferred async exception at compiled safepoint");
1598         return;
1599       }
1600     }
1601   }
1602 
1603   AsyncExceptionCondition condition = clear_async_exception_condition();
1604   if (condition == _no_async_condition) {
1605     // Conditions have changed since has_special_runtime_exit_condition()
1606     // was called:
1607     // - if we were here only because of an external suspend request,
1608     //   then that was taken care of above (or cancelled) so we are done
1609     // - if we were here because of another async request, then it has
1610     //   been cleared between the has_special_runtime_exit_condition()
1611     //   and now so again we are done
1612     return;
1613   }
1614 
1615   // Check for pending async. exception
1616   if (_pending_async_exception != NULL) {
1617     // Only overwrite an already pending exception, if it is not a threadDeath.
1618     if (!has_pending_exception() || !pending_exception()->is_a(vmClasses::ThreadDeath_klass())) {
1619 
1620       // We cannot call Exceptions::_throw(...) here because we cannot block
1621       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1622 
1623       LogTarget(Info, exceptions) lt;
1624       if (lt.is_enabled()) {
1625         ResourceMark rm;
1626         LogStream ls(lt);
1627         ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1628           if (has_last_Java_frame()) {
1629             frame f = last_frame();
1630            ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1631           }
1632         ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
1633       }
1634       _pending_async_exception = NULL;
1635       // Clear condition from _suspend_flags since we have finished processing it.
1636       clear_suspend_flag(_has_async_exception);
1637     }
1638   }
1639 
1640   if (condition == _async_unsafe_access_error && !has_pending_exception()) {
1641     // We may be at method entry which requires we save the do-not-unlock flag.
1642     UnlockFlagSaver fs(this);
1643     switch (thread_state()) {
1644     case _thread_in_vm: {
1645       JavaThread* THREAD = this;
1646       Exceptions::throw_unsafe_access_internal_error(THREAD, __FILE__, __LINE__, "a fault occurred in an unsafe memory access operation");
1647       return;
1648     }
1649     case _thread_in_native: {
1650       ThreadInVMfromNative tiv(this);
1651       JavaThread* THREAD = this;
1652       Exceptions::throw_unsafe_access_internal_error(THREAD, __FILE__, __LINE__, "a fault occurred in an unsafe memory access operation");
1653       return;
1654     }
1655     case _thread_in_Java: {
1656       ThreadInVMfromJava tiv(this);
1657       JavaThread* THREAD = this;
1658       Exceptions::throw_unsafe_access_internal_error(THREAD, __FILE__, __LINE__, "a fault occurred in an unsafe memory access operation in compiled Java code");
1659       return;
1660     }
1661     default:
1662       ShouldNotReachHere();
1663     }
1664   }
1665 
1666   assert(has_pending_exception(), "must have handled the async condition if no exception");
1667 }
1668 
1669 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1670 
1671   if (is_obj_deopt_suspend()) {
1672     frame_anchor()->make_walkable(this);
1673     wait_for_object_deoptimization();
1674   }
1675 
1676   // We might be here for reasons in addition to the self-suspend request
1677   // so check for other async requests.
1678   if (check_asyncs) {
1679     check_and_handle_async_exceptions();
1680   }
1681 
1682   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1683 }
1684 
1685 class InstallAsyncExceptionClosure : public HandshakeClosure {
1686   Handle _throwable; // The Throwable thrown at the target Thread
1687 public:
1688   InstallAsyncExceptionClosure(Handle throwable) : HandshakeClosure("InstallAsyncException"), _throwable(throwable) {}
1689 
1690   void do_thread(Thread* thr) {
1691     JavaThread* target = JavaThread::cast(thr);
1692     // Note that this now allows multiple ThreadDeath exceptions to be
1693     // thrown at a thread.
1694     // The target thread has run and has not exited yet.
1695     target->send_thread_stop(_throwable());
1696   }
1697 };
1698 
1699 void JavaThread::send_async_exception(oop java_thread, oop java_throwable) {
1700   Handle throwable(Thread::current(), java_throwable);
1701   JavaThread* target = java_lang_Thread::thread(java_thread);
1702   InstallAsyncExceptionClosure vm_stop(throwable);
1703   Handshake::execute(&vm_stop, target);
1704 }
1705 
1706 void JavaThread::send_thread_stop(oop java_throwable)  {
1707   ResourceMark rm;
1708   assert(is_handshake_safe_for(Thread::current()),
1709          "should be self or handshakee");
1710 
1711   // Do not throw asynchronous exceptions against the compiler thread
1712   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1713   if (!can_call_java()) return;
1714 
1715   {
1716     // Actually throw the Throwable against the target Thread - however
1717     // only if there is no thread death exception installed already.
1718     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(vmClasses::ThreadDeath_klass())) {
1719       // If the topmost frame is a runtime stub, then we are calling into
1720       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1721       // must deoptimize the caller before continuing, as the compiled  exception handler table
1722       // may not be valid
1723       if (has_last_Java_frame()) {
1724         frame f = last_frame();
1725         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1726           RegisterMap reg_map(this, false);
1727           frame compiled_frame = f.sender(&reg_map);
1728           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1729             Deoptimization::deoptimize(this, compiled_frame);
1730           }
1731         }
1732       }
1733 
1734       // Set async. pending exception in thread.
1735       set_pending_async_exception(java_throwable);
1736 
1737       if (log_is_enabled(Info, exceptions)) {
1738          ResourceMark rm;
1739         log_info(exceptions)("Pending Async. exception installed of type: %s",
1740                              InstanceKlass::cast(_pending_async_exception->klass())->external_name());
1741       }
1742       // for AbortVMOnException flag
1743       Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
1744     }
1745   }
1746 
1747 
1748   // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1749   java_lang_Thread::set_interrupted(threadObj(), true);
1750   this->interrupt();
1751 }
1752 
1753 
1754 // External suspension mechanism.
1755 //
1756 // Guarantees on return (for a valid target thread):
1757 //   - Target thread will not execute any new bytecode.
1758 //   - Target thread will not enter any new monitors.
1759 //
1760 bool JavaThread::java_suspend() {
1761   ThreadsListHandle tlh;
1762   if (!tlh.includes(this)) {
1763     log_trace(thread, suspend)("JavaThread:" INTPTR_FORMAT " not on ThreadsList, no suspension", p2i(this));
1764     return false;
1765   }
1766   return this->handshake_state()->suspend();
1767 }
1768 
1769 bool JavaThread::java_resume() {
1770   ThreadsListHandle tlh;
1771   if (!tlh.includes(this)) {
1772     log_trace(thread, suspend)("JavaThread:" INTPTR_FORMAT " not on ThreadsList, nothing to resume", p2i(this));
1773     return false;
1774   }
1775   return this->handshake_state()->resume();
1776 }
1777 
1778 // Wait for another thread to perform object reallocation and relocking on behalf of
1779 // this thread.
1780 // Raw thread state transition to _thread_blocked and back again to the original
1781 // state before returning are performed. The current thread is required to
1782 // change to _thread_blocked in order to be seen to be safepoint/handshake safe
1783 // whilst suspended and only after becoming handshake safe, the other thread can
1784 // complete the handshake used to synchronize with this thread and then perform
1785 // the reallocation and relocking. We cannot use the thread state transition
1786 // helpers because we arrive here in various states and also because the helpers
1787 // indirectly call this method.  After leaving _thread_blocked we have to check
1788 // for safepoint/handshake, except if _thread_in_native. The thread is safe
1789 // without blocking then. Allowed states are enumerated in
1790 // SafepointSynchronize::block(). See also EscapeBarrier::sync_and_suspend_*()
1791 
1792 void JavaThread::wait_for_object_deoptimization() {
1793   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1794   assert(this == Thread::current(), "invariant");
1795   JavaThreadState state = thread_state();
1796 
1797   bool spin_wait = os::is_MP();
1798   do {
1799     set_thread_state(_thread_blocked);
1800     // Wait for object deoptimization if requested.
1801     if (spin_wait) {
1802       // A single deoptimization is typically very short. Microbenchmarks
1803       // showed 5% better performance when spinning.
1804       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1805       SpinYield spin(spin_limit);
1806       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1807         spin.wait();
1808       }
1809       // Spin just once
1810       spin_wait = false;
1811     } else {
1812       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1813       if (is_obj_deopt_suspend()) {
1814         ml.wait();
1815       }
1816     }
1817     // The current thread could have been suspended again. We have to check for
1818     // suspend after restoring the saved state. Without this the current thread
1819     // might return to _thread_in_Java and execute bytecode.
1820     set_thread_state_fence(state);
1821 
1822     if (state != _thread_in_native) {
1823       SafepointMechanism::process_if_requested(this);
1824     }
1825     // A handshake for obj. deoptimization suspend could have been processed so
1826     // we must check after processing.
1827   } while (is_obj_deopt_suspend());
1828 }
1829 
1830 #ifdef ASSERT
1831 // Verify the JavaThread has not yet been published in the Threads::list, and
1832 // hence doesn't need protection from concurrent access at this stage.
1833 void JavaThread::verify_not_published() {
1834   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1835   // since an unpublished JavaThread doesn't participate in the
1836   // Thread-SMR protocol for keeping a ThreadsList alive.
1837   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1838 }
1839 #endif
1840 
1841 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1842 // pending, when _suspend_flags is non-zero or when we need to process a stack
1843 // watermark. Also check for pending async exceptions (except unsafe access error).
1844 // Note only the native==>Java barriers can call this function when thread state
1845 // is _thread_in_native_trans.
1846 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1847   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1848   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1849 
1850   // Enable WXWrite: called directly from interpreter native wrapper.
1851   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1852 
1853   SafepointMechanism::process_if_requested_with_exit_check(thread, false /* check asyncs */);
1854 
1855   // After returning from native, it could be that the stack frames are not
1856   // yet safe to use. We catch such situations in the subsequent stack watermark
1857   // barrier, which will trap unsafe stack frames.
1858   StackWatermarkSet::before_unwind(thread);
1859 
1860   if (thread->has_async_exception_condition(false /* check unsafe access error */)) {
1861     // We are in _thread_in_native_trans state, don't handle unsafe
1862     // access error since that may block.
1863     thread->check_and_handle_async_exceptions();
1864   }
1865 }
1866 
1867 #ifndef PRODUCT
1868 // Deoptimization
1869 // Function for testing deoptimization
1870 void JavaThread::deoptimize() {
1871   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1872   bool deopt = false;           // Dump stack only if a deopt actually happens.
1873   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1874   // Iterate over all frames in the thread and deoptimize
1875   for (; !fst.is_done(); fst.next()) {
1876     if (fst.current()->can_be_deoptimized()) {
1877 
1878       if (only_at) {
1879         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1880         // consists of comma or carriage return separated numbers so
1881         // search for the current bci in that string.
1882         address pc = fst.current()->pc();
1883         nmethod* nm =  (nmethod*) fst.current()->cb();
1884         ScopeDesc* sd = nm->scope_desc_at(pc);
1885         char buffer[8];
1886         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1887         size_t len = strlen(buffer);
1888         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1889         while (found != NULL) {
1890           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1891               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1892             // Check that the bci found is bracketed by terminators.
1893             break;
1894           }
1895           found = strstr(found + 1, buffer);
1896         }
1897         if (!found) {
1898           continue;
1899         }
1900       }
1901 
1902       if (DebugDeoptimization && !deopt) {
1903         deopt = true; // One-time only print before deopt
1904         tty->print_cr("[BEFORE Deoptimization]");
1905         trace_frames();
1906         trace_stack();
1907       }
1908       Deoptimization::deoptimize(this, *fst.current());
1909     }
1910   }
1911 
1912   if (DebugDeoptimization && deopt) {
1913     tty->print_cr("[AFTER Deoptimization]");
1914     trace_frames();
1915   }
1916 }
1917 
1918 
1919 // Make zombies
1920 void JavaThread::make_zombies() {
1921   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1922     if (fst.current()->can_be_deoptimized()) {
1923       // it is a Java nmethod
1924       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1925       nm->make_not_entrant();
1926     }
1927   }
1928 }
1929 #endif // PRODUCT
1930 
1931 
1932 void JavaThread::deoptimize_marked_methods() {
1933   if (!has_last_Java_frame()) return;
1934   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1935   for (; !fst.is_done(); fst.next()) {
1936     if (fst.current()->should_be_deoptimized()) {
1937       Deoptimization::deoptimize(this, *fst.current());
1938     }
1939   }
1940 }
1941 
1942 #ifdef ASSERT
1943 void JavaThread::verify_frame_info() {
1944   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1945          (has_last_Java_frame() && java_call_counter() > 0),
1946          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1947          has_last_Java_frame() ? "true" : "false", java_call_counter());
1948 }
1949 #endif
1950 
1951 void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
1952   // Verify that the deferred card marks have been flushed.
1953   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1954 
1955   // Traverse the GCHandles
1956   Thread::oops_do_no_frames(f, cf);
1957 
1958   DEBUG_ONLY(verify_frame_info();)
1959 
1960   if (has_last_Java_frame()) {
1961     // Traverse the monitor chunks
1962     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1963       chunk->oops_do(f);
1964     }
1965   }
1966 
1967   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
1968   // If we have deferred set_locals there might be oops waiting to be
1969   // written
1970   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1971   if (list != NULL) {
1972     for (int i = 0; i < list->length(); i++) {
1973       list->at(i)->oops_do(f);
1974     }
1975   }
1976 
1977   // Traverse instance variables at the end since the GC may be moving things
1978   // around using this function
1979   f->do_oop((oop*) &_vm_result);
1980   f->do_oop((oop*) &_exception_oop);
1981   f->do_oop((oop*) &_pending_async_exception);
1982 #if INCLUDE_JVMCI
1983   f->do_oop((oop*) &_jvmci_reserved_oop0);
1984 #endif
1985 
1986   if (jvmti_thread_state() != NULL) {
1987     jvmti_thread_state()->oops_do(f, cf);
1988   }
1989 }
1990 
1991 void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
1992   if (!has_last_Java_frame()) {
1993     return;
1994   }
1995   // Finish any pending lazy GC activity for the frames
1996   StackWatermarkSet::finish_processing(this, NULL /* context */, StackWatermarkKind::gc);
1997   // Traverse the execution stack
1998   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1999     fst.current()->oops_do(f, cf, fst.register_map());
2000   }
2001 }
2002 
2003 #ifdef ASSERT
2004 void JavaThread::verify_states_for_handshake() {
2005   // This checks that the thread has a correct frame state during a handshake.
2006   verify_frame_info();
2007 }
2008 #endif
2009 
2010 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2011   DEBUG_ONLY(verify_frame_info();)
2012 
2013   if (has_last_Java_frame()) {
2014     // Traverse the execution stack
2015     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2016       fst.current()->nmethods_do(cf);
2017     }
2018   }
2019 
2020   if (jvmti_thread_state() != NULL) {
2021     jvmti_thread_state()->nmethods_do(cf);
2022   }
2023 }
2024 
2025 void JavaThread::metadata_do(MetadataClosure* f) {
2026   if (has_last_Java_frame()) {
2027     // Traverse the execution stack to call f() on the methods in the stack
2028     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2029       fst.current()->metadata_do(f);
2030     }
2031   } else if (is_Compiler_thread()) {
2032     // need to walk ciMetadata in current compile tasks to keep alive.
2033     CompilerThread* ct = (CompilerThread*)this;
2034     if (ct->env() != NULL) {
2035       ct->env()->metadata_do(f);
2036     }
2037     CompileTask* task = ct->task();
2038     if (task != NULL) {
2039       task->metadata_do(f);
2040     }
2041   }
2042 }
2043 
2044 // Printing
2045 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2046   switch (_thread_state) {
2047   case _thread_uninitialized:     return "_thread_uninitialized";
2048   case _thread_new:               return "_thread_new";
2049   case _thread_new_trans:         return "_thread_new_trans";
2050   case _thread_in_native:         return "_thread_in_native";
2051   case _thread_in_native_trans:   return "_thread_in_native_trans";
2052   case _thread_in_vm:             return "_thread_in_vm";
2053   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2054   case _thread_in_Java:           return "_thread_in_Java";
2055   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2056   case _thread_blocked:           return "_thread_blocked";
2057   case _thread_blocked_trans:     return "_thread_blocked_trans";
2058   default:                        return "unknown thread state";
2059   }
2060 }
2061 
2062 #ifndef PRODUCT
2063 void JavaThread::print_thread_state_on(outputStream *st) const {
2064   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2065 };
2066 #endif // PRODUCT
2067 
2068 // Called by Threads::print() for VM_PrintThreads operation
2069 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
2070   st->print_raw("\"");
2071   st->print_raw(name());
2072   st->print_raw("\" ");
2073   oop thread_oop = threadObj();
2074   if (thread_oop != NULL) {
2075     st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2076     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2077     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2078   }
2079   Thread::print_on(st, print_extended_info);
2080   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2081   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2082   if (thread_oop != NULL) {
2083     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2084   }
2085 #ifndef PRODUCT
2086   _safepoint_state->print_on(st);
2087 #endif // PRODUCT
2088   if (is_Compiler_thread()) {
2089     CompileTask *task = ((CompilerThread*)this)->task();
2090     if (task != NULL) {
2091       st->print("   Compiling: ");
2092       task->print(st, NULL, true, false);
2093     } else {
2094       st->print("   No compile task");
2095     }
2096     st->cr();
2097   }
2098 }
2099 
2100 void JavaThread::print() const { print_on(tty); }
2101 
2102 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2103   st->print("%s", get_thread_name_string(buf, buflen));
2104 }
2105 
2106 // Called by fatal error handler. The difference between this and
2107 // JavaThread::print() is that we can't grab lock or allocate memory.
2108 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2109   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
2110   oop thread_obj = threadObj();
2111   if (thread_obj != NULL) {
2112     if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2113   }
2114   st->print(" [");
2115   st->print("%s", _get_thread_state_name(_thread_state));
2116   if (osthread()) {
2117     st->print(", id=%d", osthread()->thread_id());
2118   }
2119   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2120             p2i(stack_end()), p2i(stack_base()));
2121   st->print("]");
2122 
2123   ThreadsSMRSupport::print_info_on(this, st);
2124   return;
2125 }
2126 
2127 
2128 // Verification
2129 
2130 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2131   // ignore if there is no stack
2132   if (!has_last_Java_frame()) return;
2133   // traverse the stack frames. Starts from top frame.
2134   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2135     frame* fr = fst.current();
2136     f(fr, fst.register_map());
2137   }
2138 }
2139 
2140 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2141 
2142 void JavaThread::verify() {
2143   // Verify oops in the thread.
2144   oops_do(&VerifyOopClosure::verify_oop, NULL);
2145 
2146   // Verify the stack frames.
2147   frames_do(frame_verify);
2148 }
2149 
2150 // CR 6300358 (sub-CR 2137150)
2151 // Most callers of this method assume that it can't return NULL but a
2152 // thread may not have a name whilst it is in the process of attaching to
2153 // the VM - see CR 6412693, and there are places where a JavaThread can be
2154 // seen prior to having its threadObj set (e.g., JNI attaching threads and
2155 // if vm exit occurs during initialization). These cases can all be accounted
2156 // for such that this method never returns NULL.
2157 const char* JavaThread::name() const  {
2158   if (Thread::is_JavaThread_protected(this)) {
2159     // The target JavaThread is protected so get_thread_name_string() is safe:
2160     return get_thread_name_string();
2161   }
2162 
2163   // The target JavaThread is not protected so we return the default:
2164   return Thread::name();
2165 }
2166 
2167 // Returns a non-NULL representation of this thread's name, or a suitable
2168 // descriptive string if there is no set name.
2169 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2170   const char* name_str;
2171   oop thread_obj = threadObj();
2172   if (thread_obj != NULL) {
2173     oop name = java_lang_Thread::name(thread_obj);
2174     if (name != NULL) {
2175       if (buf == NULL) {
2176         name_str = java_lang_String::as_utf8_string(name);
2177       } else {
2178         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2179       }
2180     } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2181       name_str = "<no-name - thread is attaching>";
2182     } else {
2183       name_str = "<un-named>";
2184     }
2185   } else {
2186     name_str = Thread::name();
2187   }
2188   assert(name_str != NULL, "unexpected NULL thread name");
2189   return name_str;
2190 }
2191 
2192 // Helper to extract the name from the thread oop for logging.
2193 const char* JavaThread::name_for(oop thread_obj) {
2194   assert(thread_obj != NULL, "precondition");
2195   oop name = java_lang_Thread::name(thread_obj);
2196   const char* name_str;
2197   if (name != NULL) {
2198     name_str = java_lang_String::as_utf8_string(name);
2199   } else {
2200     name_str = "<un-named>";
2201   }
2202   return name_str;
2203 }
2204 
2205 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2206 
2207   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2208   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
2209   // Link Java Thread object <-> C++ Thread
2210 
2211   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2212   // and put it into a new Handle.  The Handle "thread_oop" can then
2213   // be used to pass the C++ thread object to other methods.
2214 
2215   // Set the Java level thread object (jthread) field of the
2216   // new thread (a JavaThread *) to C++ thread object using the
2217   // "thread_oop" handle.
2218 
2219   // Set the thread field (a JavaThread *) of the
2220   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2221 
2222   Handle thread_oop(Thread::current(),
2223                     JNIHandles::resolve_non_null(jni_thread));
2224   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2225          "must be initialized");
2226   set_threadObj(thread_oop());
2227   java_lang_Thread::set_thread(thread_oop(), this);
2228 
2229   if (prio == NoPriority) {
2230     prio = java_lang_Thread::priority(thread_oop());
2231     assert(prio != NoPriority, "A valid priority should be present");
2232   }
2233 
2234   // Push the Java priority down to the native thread; needs Threads_lock
2235   Thread::set_priority(this, prio);
2236 
2237   // Add the new thread to the Threads list and set it in motion.
2238   // We must have threads lock in order to call Threads::add.
2239   // It is crucial that we do not block before the thread is
2240   // added to the Threads list for if a GC happens, then the java_thread oop
2241   // will not be visited by GC.
2242   Threads::add(this);
2243 }
2244 
2245 oop JavaThread::current_park_blocker() {
2246   // Support for JSR-166 locks
2247   oop thread_oop = threadObj();
2248   if (thread_oop != NULL) {
2249     return java_lang_Thread::park_blocker(thread_oop);
2250   }
2251   return NULL;
2252 }
2253 
2254 
2255 void JavaThread::print_stack_on(outputStream* st) {
2256   if (!has_last_Java_frame()) return;
2257 
2258   Thread* current_thread = Thread::current();
2259   ResourceMark rm(current_thread);
2260   HandleMark hm(current_thread);
2261 
2262   RegisterMap reg_map(this);
2263   vframe* start_vf = last_java_vframe(&reg_map);
2264   int count = 0;
2265   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
2266     if (f->is_java_frame()) {
2267       javaVFrame* jvf = javaVFrame::cast(f);
2268       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2269 
2270       // Print out lock information
2271       if (JavaMonitorsInStackTrace) {
2272         jvf->print_lock_info_on(st, count);
2273       }
2274     } else {
2275       // Ignore non-Java frames
2276     }
2277 
2278     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
2279     count++;
2280     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
2281   }
2282 }
2283 
2284 
2285 // JVMTI PopFrame support
2286 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2287   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2288   if (in_bytes(size_in_bytes) != 0) {
2289     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2290     _popframe_preserved_args_size = in_bytes(size_in_bytes);
2291     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2292   }
2293 }
2294 
2295 void* JavaThread::popframe_preserved_args() {
2296   return _popframe_preserved_args;
2297 }
2298 
2299 ByteSize JavaThread::popframe_preserved_args_size() {
2300   return in_ByteSize(_popframe_preserved_args_size);
2301 }
2302 
2303 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2304   int sz = in_bytes(popframe_preserved_args_size());
2305   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2306   return in_WordSize(sz / wordSize);
2307 }
2308 
2309 void JavaThread::popframe_free_preserved_args() {
2310   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2311   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
2312   _popframe_preserved_args = NULL;
2313   _popframe_preserved_args_size = 0;
2314 }
2315 
2316 #ifndef PRODUCT
2317 
2318 void JavaThread::trace_frames() {
2319   tty->print_cr("[Describe stack]");
2320   int frame_no = 1;
2321   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2322     tty->print("  %d. ", frame_no++);
2323     fst.current()->print_value_on(tty, this);
2324     tty->cr();
2325   }
2326 }
2327 
2328 class PrintAndVerifyOopClosure: public OopClosure {
2329  protected:
2330   template <class T> inline void do_oop_work(T* p) {
2331     oop obj = RawAccess<>::oop_load(p);
2332     if (obj == NULL) return;
2333     tty->print(INTPTR_FORMAT ": ", p2i(p));
2334     if (oopDesc::is_oop_or_null(obj)) {
2335       if (obj->is_objArray()) {
2336         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
2337       } else {
2338         obj->print();
2339       }
2340     } else {
2341       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
2342     }
2343     tty->cr();
2344   }
2345  public:
2346   virtual void do_oop(oop* p) { do_oop_work(p); }
2347   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
2348 };
2349 
2350 #ifdef ASSERT
2351 // Print or validate the layout of stack frames
2352 void JavaThread::print_frame_layout(int depth, bool validate_only) {
2353   ResourceMark rm;
2354   PreserveExceptionMark pm(this);
2355   FrameValues values;
2356   int frame_no = 0;
2357   for (StackFrameStream fst(this, false /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2358     fst.current()->describe(values, ++frame_no);
2359     if (depth == frame_no) break;
2360   }
2361   if (validate_only) {
2362     values.validate();
2363   } else {
2364     tty->print_cr("[Describe stack layout]");
2365     values.print(this);
2366   }
2367 }
2368 #endif
2369 
2370 void JavaThread::trace_stack_from(vframe* start_vf) {
2371   ResourceMark rm;
2372   int vframe_no = 1;
2373   for (vframe* f = start_vf; f; f = f->sender()) {
2374     if (f->is_java_frame()) {
2375       javaVFrame::cast(f)->print_activation(vframe_no++);
2376     } else {
2377       f->print();
2378     }
2379     if (vframe_no > StackPrintLimit) {
2380       tty->print_cr("...<more frames>...");
2381       return;
2382     }
2383   }
2384 }
2385 
2386 
2387 void JavaThread::trace_stack() {
2388   if (!has_last_Java_frame()) return;
2389   Thread* current_thread = Thread::current();
2390   ResourceMark rm(current_thread);
2391   HandleMark hm(current_thread);
2392   RegisterMap reg_map(this);
2393   trace_stack_from(last_java_vframe(&reg_map));
2394 }
2395 
2396 
2397 #endif // PRODUCT
2398 
2399 
2400 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2401   assert(reg_map != NULL, "a map must be given");
2402   frame f = last_frame();
2403   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2404     if (vf->is_java_frame()) return javaVFrame::cast(vf);
2405   }
2406   return NULL;
2407 }
2408 
2409 
2410 Klass* JavaThread::security_get_caller_class(int depth) {
2411   vframeStream vfst(this);
2412   vfst.security_get_caller_frame(depth);
2413   if (!vfst.at_end()) {
2414     return vfst.method()->method_holder();
2415   }
2416   return NULL;
2417 }
2418 
2419 // java.lang.Thread.sleep support
2420 // Returns true if sleep time elapsed as expected, and false
2421 // if the thread was interrupted.
2422 bool JavaThread::sleep(jlong millis) {
2423   assert(this == Thread::current(),  "thread consistency check");
2424 
2425   ParkEvent * const slp = this->_SleepEvent;
2426   // Because there can be races with thread interruption sending an unpark()
2427   // to the event, we explicitly reset it here to avoid an immediate return.
2428   // The actual interrupt state will be checked before we park().
2429   slp->reset();
2430   // Thread interruption establishes a happens-before ordering in the
2431   // Java Memory Model, so we need to ensure we synchronize with the
2432   // interrupt state.
2433   OrderAccess::fence();
2434 
2435   jlong prevtime = os::javaTimeNanos();
2436 
2437   for (;;) {
2438     // interruption has precedence over timing out
2439     if (this->is_interrupted(true)) {
2440       return false;
2441     }
2442 
2443     if (millis <= 0) {
2444       return true;
2445     }
2446 
2447     {
2448       ThreadBlockInVM tbivm(this);
2449       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2450       slp->park(millis);
2451     }
2452 
2453     // Update elapsed time tracking
2454     jlong newtime = os::javaTimeNanos();
2455     if (newtime - prevtime < 0) {
2456       // time moving backwards, should only happen if no monotonic clock
2457       // not a guarantee() because JVM should not abort on kernel/glibc bugs
2458       assert(false,
2459              "unexpected time moving backwards detected in JavaThread::sleep()");
2460     } else {
2461       millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
2462     }
2463     prevtime = newtime;
2464   }
2465 }
2466 
2467 
2468 // ======= Threads ========
2469 
2470 // The Threads class links together all active threads, and provides
2471 // operations over all threads. It is protected by the Threads_lock,
2472 // which is also used in other global contexts like safepointing.
2473 // ThreadsListHandles are used to safely perform operations on one
2474 // or more threads without the risk of the thread exiting during the
2475 // operation.
2476 //
2477 // Note: The Threads_lock is currently more widely used than we
2478 // would like. We are actively migrating Threads_lock uses to other
2479 // mechanisms in order to reduce Threads_lock contention.
2480 
2481 int         Threads::_number_of_threads = 0;
2482 int         Threads::_number_of_non_daemon_threads = 0;
2483 int         Threads::_return_code = 0;
2484 uintx       Threads::_thread_claim_token = 1; // Never zero.
2485 size_t      JavaThread::_stack_size_at_create = 0;
2486 
2487 #ifdef ASSERT
2488 bool        Threads::_vm_complete = false;
2489 #endif
2490 
2491 // All NonJavaThreads (i.e., every non-JavaThread in the system).
2492 void Threads::non_java_threads_do(ThreadClosure* tc) {
2493   NoSafepointVerifier nsv;
2494   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
2495     tc->do_thread(njti.current());
2496   }
2497 }
2498 
2499 // All JavaThreads
2500 #define ALL_JAVA_THREADS(X) \
2501   for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
2502 
2503 // All JavaThreads
2504 void Threads::java_threads_do(ThreadClosure* tc) {
2505   assert_locked_or_safepoint(Threads_lock);
2506   // ALL_JAVA_THREADS iterates through all JavaThreads.
2507   ALL_JAVA_THREADS(p) {
2508     tc->do_thread(p);
2509   }
2510 }
2511 
2512 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
2513   assert_locked_or_safepoint(Threads_lock);
2514   java_threads_do(tc);
2515   tc->do_thread(VMThread::vm_thread());
2516 }
2517 
2518 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
2519 void Threads::threads_do(ThreadClosure* tc) {
2520   assert_locked_or_safepoint(Threads_lock);
2521   java_threads_do(tc);
2522   non_java_threads_do(tc);
2523 }
2524 
2525 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
2526   uintx claim_token = Threads::thread_claim_token();
2527   ALL_JAVA_THREADS(p) {
2528     if (p->claim_threads_do(is_par, claim_token)) {
2529       tc->do_thread(p);
2530     }
2531   }
2532   VMThread* vmt = VMThread::vm_thread();
2533   if (vmt->claim_threads_do(is_par, claim_token)) {
2534     tc->do_thread(vmt);
2535   }
2536 }
2537 
2538 // The system initialization in the library has three phases.
2539 //
2540 // Phase 1: java.lang.System class initialization
2541 //     java.lang.System is a primordial class loaded and initialized
2542 //     by the VM early during startup.  java.lang.System.<clinit>
2543 //     only does registerNatives and keeps the rest of the class
2544 //     initialization work later until thread initialization completes.
2545 //
2546 //     System.initPhase1 initializes the system properties, the static
2547 //     fields in, out, and err. Set up java signal handlers, OS-specific
2548 //     system settings, and thread group of the main thread.
2549 static void call_initPhase1(TRAPS) {
2550   Klass* klass = vmClasses::System_klass();
2551   JavaValue result(T_VOID);
2552   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
2553                                          vmSymbols::void_method_signature(), CHECK);
2554 }
2555 
2556 // Phase 2. Module system initialization
2557 //     This will initialize the module system.  Only java.base classes
2558 //     can be loaded until phase 2 completes.
2559 //
2560 //     Call System.initPhase2 after the compiler initialization and jsr292
2561 //     classes get initialized because module initialization runs a lot of java
2562 //     code, that for performance reasons, should be compiled.  Also, this will
2563 //     enable the startup code to use lambda and other language features in this
2564 //     phase and onward.
2565 //
2566 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
2567 static void call_initPhase2(TRAPS) {
2568   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
2569 
2570   Klass* klass = vmClasses::System_klass();
2571 
2572   JavaValue result(T_INT);
2573   JavaCallArguments args;
2574   args.push_int(DisplayVMOutputToStderr);
2575   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
2576   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
2577                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
2578   if (result.get_jint() != JNI_OK) {
2579     vm_exit_during_initialization(); // no message or exception
2580   }
2581 
2582   universe_post_module_init();
2583 }
2584 
2585 // Phase 3. final setup - set security manager, system class loader and TCCL
2586 //
2587 //     This will instantiate and set the security manager, set the system class
2588 //     loader as well as the thread context class loader.  The security manager
2589 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
2590 //     other modules or the application's classpath.
2591 static void call_initPhase3(TRAPS) {
2592   Klass* klass = vmClasses::System_klass();
2593   JavaValue result(T_VOID);
2594   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
2595                                          vmSymbols::void_method_signature(), CHECK);
2596 }
2597 
2598 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
2599   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
2600 
2601   if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2602     create_vm_init_libraries();
2603   }
2604 
2605   initialize_class(vmSymbols::java_lang_String(), CHECK);
2606 
2607   // Inject CompactStrings value after the static initializers for String ran.
2608   java_lang_String::set_compact_strings(CompactStrings);
2609 
2610   // Initialize java_lang.System (needed before creating the thread)
2611   initialize_class(vmSymbols::java_lang_System(), CHECK);
2612   // The VM creates & returns objects of this class. Make sure it's initialized.
2613   initialize_class(vmSymbols::java_lang_Class(), CHECK);
2614   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
2615   Handle thread_group = create_initial_thread_group(CHECK);
2616   Universe::set_main_thread_group(thread_group());
2617   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
2618   create_initial_thread(thread_group, main_thread, CHECK);
2619 
2620   // The VM creates objects of this class.
2621   initialize_class(vmSymbols::java_lang_Module(), CHECK);
2622 
2623 #ifdef ASSERT
2624   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
2625   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
2626 #endif
2627 
2628   // initialize the hardware-specific constants needed by Unsafe
2629   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
2630   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
2631 
2632   // The VM preresolves methods to these classes. Make sure that they get initialized
2633   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
2634   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
2635 
2636   // Phase 1 of the system initialization in the library, java.lang.System class initialization
2637   call_initPhase1(CHECK);
2638 
2639   // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
2640   // Some values are actually configure-time constants but some can be set via the jlink tool and
2641   // so must be read dynamically. We treat them all the same.
2642   InstanceKlass* ik = SystemDictionary::find_instance_klass(vmSymbols::java_lang_VersionProps(),
2643                                                             Handle(), Handle());
2644   {
2645     ResourceMark rm(main_thread);
2646     JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
2647 
2648     JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
2649 
2650     JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
2651 
2652     JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
2653 
2654     JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
2655   }
2656 
2657   // an instance of OutOfMemory exception has been allocated earlier
2658   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
2659   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
2660   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
2661   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
2662   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
2663   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
2664   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
2665   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
2666 }
2667 
2668 void Threads::initialize_jsr292_core_classes(TRAPS) {
2669   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
2670 
2671   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
2672   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
2673   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
2674   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
2675 }
2676 
2677 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2678   extern void JDK_Version_init();
2679 
2680   // Preinitialize version info.
2681   VM_Version::early_initialize();
2682 
2683   // Check version
2684   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2685 
2686   // Initialize library-based TLS
2687   ThreadLocalStorage::init();
2688 
2689   // Initialize the output stream module
2690   ostream_init();
2691 
2692   // Process java launcher properties.
2693   Arguments::process_sun_java_launcher_properties(args);
2694 
2695   // Initialize the os module
2696   os::init();
2697 
2698   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
2699 
2700   // Record VM creation timing statistics
2701   TraceVmCreationTime create_vm_timer;
2702   create_vm_timer.start();
2703 
2704   // Initialize system properties.
2705   Arguments::init_system_properties();
2706 
2707   // So that JDK version can be used as a discriminator when parsing arguments
2708   JDK_Version_init();
2709 
2710   // Update/Initialize System properties after JDK version number is known
2711   Arguments::init_version_specific_system_properties();
2712 
2713   // Make sure to initialize log configuration *before* parsing arguments
2714   LogConfiguration::initialize(create_vm_timer.begin_time());
2715 
2716   // Parse arguments
2717   // Note: this internally calls os::init_container_support()
2718   jint parse_result = Arguments::parse(args);
2719   if (parse_result != JNI_OK) return parse_result;
2720 
2721 #if INCLUDE_NMT
2722   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
2723   MemTracker::initialize();
2724 #endif // INCLUDE_NMT
2725 
2726   os::init_before_ergo();
2727 
2728   jint ergo_result = Arguments::apply_ergo();
2729   if (ergo_result != JNI_OK) return ergo_result;
2730 
2731   // Final check of all ranges after ergonomics which may change values.
2732   if (!JVMFlagLimit::check_all_ranges()) {
2733     return JNI_EINVAL;
2734   }
2735 
2736   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
2737   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
2738   if (!constraint_result) {
2739     return JNI_EINVAL;
2740   }
2741 
2742   if (PauseAtStartup) {
2743     os::pause();
2744   }
2745 
2746   HOTSPOT_VM_INIT_BEGIN();
2747 
2748   // Timing (must come after argument parsing)
2749   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
2750 
2751   // Initialize the os module after parsing the args
2752   jint os_init_2_result = os::init_2();
2753   if (os_init_2_result != JNI_OK) return os_init_2_result;
2754 
2755 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
2756   // Initialize assert poison page mechanism.
2757   if (ShowRegistersOnAssert) {
2758     initialize_assert_poison();
2759   }
2760 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
2761 
2762   SafepointMechanism::initialize();
2763 
2764   jint adjust_after_os_result = Arguments::adjust_after_os();
2765   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
2766 
2767   // Initialize output stream logging
2768   ostream_init_log();
2769 
2770   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2771   // Must be before create_vm_init_agents()
2772   if (Arguments::init_libraries_at_startup()) {
2773     convert_vm_init_libraries_to_agents();
2774   }
2775 
2776   // Launch -agentlib/-agentpath and converted -Xrun agents
2777   if (Arguments::init_agents_at_startup()) {
2778     create_vm_init_agents();
2779   }
2780 
2781   // Initialize Threads state
2782   _number_of_threads = 0;
2783   _number_of_non_daemon_threads = 0;
2784 
2785   // Initialize global data structures and create system classes in heap
2786   vm_init_globals();
2787 
2788 #if INCLUDE_JVMCI
2789   if (JVMCICounterSize > 0) {
2790     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
2791     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
2792   } else {
2793     JavaThread::_jvmci_old_thread_counters = NULL;
2794   }
2795 #endif // INCLUDE_JVMCI
2796 
2797   // Initialize OopStorage for threadObj
2798   _thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
2799 
2800   // Attach the main thread to this os thread
2801   JavaThread* main_thread = new JavaThread();
2802   main_thread->set_thread_state(_thread_in_vm);
2803   main_thread->initialize_thread_current();
2804   // must do this before set_active_handles
2805   main_thread->record_stack_base_and_size();
2806   main_thread->register_thread_stack_with_NMT();
2807   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2808   MACOS_AARCH64_ONLY(main_thread->init_wx());
2809 
2810   if (!main_thread->set_as_starting_thread()) {
2811     vm_shutdown_during_initialization(
2812                                       "Failed necessary internal allocation. Out of swap space");
2813     main_thread->smr_delete();
2814     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2815     return JNI_ENOMEM;
2816   }
2817 
2818   // Enable guard page *after* os::create_main_thread(), otherwise it would
2819   // crash Linux VM, see notes in os_linux.cpp.
2820   main_thread->stack_overflow_state()->create_stack_guard_pages();
2821 
2822   // Initialize Java-Level synchronization subsystem
2823   ObjectMonitor::Initialize();
2824   ObjectSynchronizer::initialize();
2825 
2826   // Initialize global modules
2827   jint status = init_globals();
2828   if (status != JNI_OK) {
2829     main_thread->smr_delete();
2830     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2831     return status;
2832   }
2833 
2834   JFR_ONLY(Jfr::on_create_vm_1();)
2835 
2836   // Should be done after the heap is fully created
2837   main_thread->cache_global_variables();
2838 
2839   { MutexLocker mu(Threads_lock);
2840     Threads::add(main_thread);
2841   }
2842 
2843   // Any JVMTI raw monitors entered in onload will transition into
2844   // real raw monitor. VM is setup enough here for raw monitor enter.
2845   JvmtiExport::transition_pending_onload_raw_monitors();
2846 
2847   // Create the VMThread
2848   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
2849 
2850     VMThread::create();
2851     Thread* vmthread = VMThread::vm_thread();
2852 
2853     if (!os::create_thread(vmthread, os::vm_thread)) {
2854       vm_exit_during_initialization("Cannot create VM thread. "
2855                                     "Out of system resources.");
2856     }
2857 
2858     // Wait for the VM thread to become ready, and VMThread::run to initialize
2859     // Monitors can have spurious returns, must always check another state flag
2860     {
2861       MonitorLocker ml(Notify_lock);
2862       os::start_thread(vmthread);
2863       while (vmthread->active_handles() == NULL) {
2864         ml.wait();
2865       }
2866     }
2867   }
2868 
2869   assert(Universe::is_fully_initialized(), "not initialized");
2870   if (VerifyDuringStartup) {
2871     // Make sure we're starting with a clean slate.
2872     VM_Verify verify_op;
2873     VMThread::execute(&verify_op);
2874   }
2875 
2876   // We need this to update the java.vm.info property in case any flags used
2877   // to initially define it have been changed. This is needed for both CDS
2878   // since UseSharedSpaces may be changed after java.vm.info
2879   // is initially computed. See Abstract_VM_Version::vm_info_string().
2880   // This update must happen before we initialize the java classes, but
2881   // after any initialization logic that might modify the flags.
2882   Arguments::update_vm_info_property(VM_Version::vm_info_string());
2883 
2884   JavaThread* THREAD = JavaThread::current(); // For exception macros.
2885   HandleMark hm(THREAD);
2886 
2887   // Always call even when there are not JVMTI environments yet, since environments
2888   // may be attached late and JVMTI must track phases of VM execution
2889   JvmtiExport::enter_early_start_phase();
2890 
2891   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2892   JvmtiExport::post_early_vm_start();
2893 
2894   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
2895 
2896   quicken_jni_functions();
2897 
2898   // No more stub generation allowed after that point.
2899   StubCodeDesc::freeze();
2900 
2901   // Set flag that basic initialization has completed. Used by exceptions and various
2902   // debug stuff, that does not work until all basic classes have been initialized.
2903   set_init_completed();
2904 
2905   LogConfiguration::post_initialize();
2906   Metaspace::post_initialize();
2907 
2908   HOTSPOT_VM_INIT_END();
2909 
2910   // record VM initialization completion time
2911 #if INCLUDE_MANAGEMENT
2912   Management::record_vm_init_completed();
2913 #endif // INCLUDE_MANAGEMENT
2914 
2915   // Signal Dispatcher needs to be started before VMInit event is posted
2916   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
2917 
2918   // Start Attach Listener if +StartAttachListener or it can't be started lazily
2919   if (!DisableAttachMechanism) {
2920     AttachListener::vm_start();
2921     if (StartAttachListener || AttachListener::init_at_startup()) {
2922       AttachListener::init();
2923     }
2924   }
2925 
2926   // Launch -Xrun agents
2927   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
2928   // back-end can launch with -Xdebug -Xrunjdwp.
2929   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
2930     create_vm_init_libraries();
2931   }
2932 
2933   Chunk::start_chunk_pool_cleaner_task();
2934 
2935   // Start the service thread
2936   // The service thread enqueues JVMTI deferred events and does various hashtable
2937   // and other cleanups.  Needs to start before the compilers start posting events.
2938   ServiceThread::initialize();
2939 
2940   // Start the monitor deflation thread:
2941   MonitorDeflationThread::initialize();
2942 
2943   // initialize compiler(s)
2944 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
2945 #if INCLUDE_JVMCI
2946   bool force_JVMCI_intialization = false;
2947   if (EnableJVMCI) {
2948     // Initialize JVMCI eagerly when it is explicitly requested.
2949     // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
2950     force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
2951 
2952     if (!force_JVMCI_intialization) {
2953       // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
2954       // compilations via JVMCI will not actually block until JVMCI is initialized.
2955       force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
2956     }
2957   }
2958 #endif
2959   CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
2960   // Postpone completion of compiler initialization to after JVMCI
2961   // is initialized to avoid timeouts of blocking compilations.
2962   if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
2963     CompileBroker::compilation_init_phase2();
2964   }
2965 #endif
2966 
2967   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
2968   // It is done after compilers are initialized, because otherwise compilations of
2969   // signature polymorphic MH intrinsics can be missed
2970   // (see SystemDictionary::find_method_handle_intrinsic).
2971   initialize_jsr292_core_classes(CHECK_JNI_ERR);
2972 
2973   // This will initialize the module system.  Only java.base classes can be
2974   // loaded until phase 2 completes
2975   call_initPhase2(CHECK_JNI_ERR);
2976 
2977   JFR_ONLY(Jfr::on_create_vm_2();)
2978 
2979   // Always call even when there are not JVMTI environments yet, since environments
2980   // may be attached late and JVMTI must track phases of VM execution
2981   JvmtiExport::enter_start_phase();
2982 
2983   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2984   JvmtiExport::post_vm_start();
2985 
2986   // Final system initialization including security manager and system class loader
2987   call_initPhase3(CHECK_JNI_ERR);
2988 
2989   // cache the system and platform class loaders
2990   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
2991 
2992 #if INCLUDE_CDS
2993   // capture the module path info from the ModuleEntryTable
2994   ClassLoader::initialize_module_path(THREAD);
2995   if (HAS_PENDING_EXCEPTION) {
2996     java_lang_Throwable::print(PENDING_EXCEPTION, tty);
2997     vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
2998   }
2999 #endif
3000 
3001 #if INCLUDE_JVMCI
3002   if (force_JVMCI_intialization) {
3003     JVMCI::initialize_compiler(CHECK_JNI_ERR);
3004     CompileBroker::compilation_init_phase2();
3005   }
3006 #endif
3007 
3008   // Always call even when there are not JVMTI environments yet, since environments
3009   // may be attached late and JVMTI must track phases of VM execution
3010   JvmtiExport::enter_live_phase();
3011 
3012   // Make perfmemory accessible
3013   PerfMemory::set_accessible(true);
3014 
3015   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3016   JvmtiExport::post_vm_initialized();
3017 
3018   JFR_ONLY(Jfr::on_create_vm_3();)
3019 
3020 #if INCLUDE_MANAGEMENT
3021   Management::initialize(THREAD);
3022 
3023   if (HAS_PENDING_EXCEPTION) {
3024     // management agent fails to start possibly due to
3025     // configuration problem and is responsible for printing
3026     // stack trace if appropriate. Simply exit VM.
3027     vm_exit(1);
3028   }
3029 #endif // INCLUDE_MANAGEMENT
3030 
3031   StatSampler::engage();
3032   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3033 
3034 #if INCLUDE_RTM_OPT
3035   RTMLockingCounters::init();
3036 #endif
3037 
3038   call_postVMInitHook(THREAD);
3039   // The Java side of PostVMInitHook.run must deal with all
3040   // exceptions and provide means of diagnosis.
3041   if (HAS_PENDING_EXCEPTION) {
3042     CLEAR_PENDING_EXCEPTION;
3043   }
3044 
3045   {
3046     MutexLocker ml(PeriodicTask_lock);
3047     // Make sure the WatcherThread can be started by WatcherThread::start()
3048     // or by dynamic enrollment.
3049     WatcherThread::make_startable();
3050     // Start up the WatcherThread if there are any periodic tasks
3051     // NOTE:  All PeriodicTasks should be registered by now. If they
3052     //   aren't, late joiners might appear to start slowly (we might
3053     //   take a while to process their first tick).
3054     if (PeriodicTask::num_tasks() > 0) {
3055       WatcherThread::start();
3056     }
3057   }
3058 
3059   create_vm_timer.end();
3060 #ifdef ASSERT
3061   _vm_complete = true;
3062 #endif
3063 
3064   if (DumpSharedSpaces) {
3065     MetaspaceShared::preload_and_dump();
3066     ShouldNotReachHere();
3067   }
3068 
3069   return JNI_OK;
3070 }
3071 
3072 // type for the Agent_OnLoad and JVM_OnLoad entry points
3073 extern "C" {
3074   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3075 }
3076 // Find a command line agent library and return its entry point for
3077 //         -agentlib:  -agentpath:   -Xrun
3078 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3079 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3080                                     const char *on_load_symbols[],
3081                                     size_t num_symbol_entries) {
3082   OnLoadEntry_t on_load_entry = NULL;
3083   void *library = NULL;
3084 
3085   if (!agent->valid()) {
3086     char buffer[JVM_MAXPATHLEN];
3087     char ebuf[1024] = "";
3088     const char *name = agent->name();
3089     const char *msg = "Could not find agent library ";
3090 
3091     // First check to see if agent is statically linked into executable
3092     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3093       library = agent->os_lib();
3094     } else if (agent->is_absolute_path()) {
3095       library = os::dll_load(name, ebuf, sizeof ebuf);
3096       if (library == NULL) {
3097         const char *sub_msg = " in absolute path, with error: ";
3098         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3099         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3100         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3101         // If we can't find the agent, exit.
3102         vm_exit_during_initialization(buf, NULL);
3103         FREE_C_HEAP_ARRAY(char, buf);
3104       }
3105     } else {
3106       // Try to load the agent from the standard dll directory
3107       if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3108                              name)) {
3109         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3110       }
3111       if (library == NULL) { // Try the library path directory.
3112         if (os::dll_build_name(buffer, sizeof(buffer), name)) {
3113           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3114         }
3115         if (library == NULL) {
3116           const char *sub_msg = " on the library path, with error: ";
3117           const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
3118 
3119           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
3120                        strlen(ebuf) + strlen(sub_msg2) + 1;
3121           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3122           if (!agent->is_instrument_lib()) {
3123             jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3124           } else {
3125             jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
3126           }
3127           // If we can't find the agent, exit.
3128           vm_exit_during_initialization(buf, NULL);
3129           FREE_C_HEAP_ARRAY(char, buf);
3130         }
3131       }
3132     }
3133     agent->set_os_lib(library);
3134     agent->set_valid();
3135   }
3136 
3137   // Find the OnLoad function.
3138   on_load_entry =
3139     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3140                                                           false,
3141                                                           on_load_symbols,
3142                                                           num_symbol_entries));
3143   return on_load_entry;
3144 }
3145 
3146 // Find the JVM_OnLoad entry point
3147 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3148   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3149   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3150 }
3151 
3152 // Find the Agent_OnLoad entry point
3153 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3154   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3155   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3156 }
3157 
3158 // For backwards compatibility with -Xrun
3159 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3160 // treated like -agentpath:
3161 // Must be called before agent libraries are created
3162 void Threads::convert_vm_init_libraries_to_agents() {
3163   AgentLibrary* agent;
3164   AgentLibrary* next;
3165 
3166   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3167     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3168     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3169 
3170     // If there is an JVM_OnLoad function it will get called later,
3171     // otherwise see if there is an Agent_OnLoad
3172     if (on_load_entry == NULL) {
3173       on_load_entry = lookup_agent_on_load(agent);
3174       if (on_load_entry != NULL) {
3175         // switch it to the agent list -- so that Agent_OnLoad will be called,
3176         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3177         Arguments::convert_library_to_agent(agent);
3178       } else {
3179         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3180       }
3181     }
3182   }
3183 }
3184 
3185 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3186 // Invokes Agent_OnLoad
3187 // Called very early -- before JavaThreads exist
3188 void Threads::create_vm_init_agents() {
3189   extern struct JavaVM_ main_vm;
3190   AgentLibrary* agent;
3191 
3192   JvmtiExport::enter_onload_phase();
3193 
3194   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3195     // CDS dumping does not support native JVMTI agent.
3196     // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
3197     if (Arguments::is_dumping_archive()) {
3198       if(!agent->is_instrument_lib()) {
3199         vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
3200       } else if (!AllowArchivingWithJavaAgent) {
3201         vm_exit_during_cds_dumping(
3202           "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
3203       }
3204     }
3205 
3206     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3207 
3208     if (on_load_entry != NULL) {
3209       // Invoke the Agent_OnLoad function
3210       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3211       if (err != JNI_OK) {
3212         vm_exit_during_initialization("agent library failed to init", agent->name());
3213       }
3214     } else {
3215       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3216     }
3217   }
3218 
3219   JvmtiExport::enter_primordial_phase();
3220 }
3221 
3222 extern "C" {
3223   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3224 }
3225 
3226 void Threads::shutdown_vm_agents() {
3227   // Send any Agent_OnUnload notifications
3228   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3229   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3230   extern struct JavaVM_ main_vm;
3231   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3232 
3233     // Find the Agent_OnUnload function.
3234     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3235                                                    os::find_agent_function(agent,
3236                                                    false,
3237                                                    on_unload_symbols,
3238                                                    num_symbol_entries));
3239 
3240     // Invoke the Agent_OnUnload function
3241     if (unload_entry != NULL) {
3242       JavaThread* thread = JavaThread::current();
3243       ThreadToNativeFromVM ttn(thread);
3244       HandleMark hm(thread);
3245       (*unload_entry)(&main_vm);
3246     }
3247   }
3248 }
3249 
3250 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3251 // Invokes JVM_OnLoad
3252 void Threads::create_vm_init_libraries() {
3253   extern struct JavaVM_ main_vm;
3254   AgentLibrary* agent;
3255 
3256   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3257     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3258 
3259     if (on_load_entry != NULL) {
3260       // Invoke the JVM_OnLoad function
3261       JavaThread* thread = JavaThread::current();
3262       ThreadToNativeFromVM ttn(thread);
3263       HandleMark hm(thread);
3264       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3265       if (err != JNI_OK) {
3266         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3267       }
3268     } else {
3269       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3270     }
3271   }
3272 }
3273 
3274 
3275 // Last thread running calls java.lang.Shutdown.shutdown()
3276 void JavaThread::invoke_shutdown_hooks() {
3277   HandleMark hm(this);
3278 
3279   // We could get here with a pending exception, if so clear it now or
3280   // it will cause MetaspaceShared::link_shared_classes to
3281   // fail for dynamic dump.
3282   if (this->has_pending_exception()) {
3283     this->clear_pending_exception();
3284   }
3285 
3286 #if INCLUDE_CDS
3287   // Link all classes for dynamic CDS dumping before vm exit.
3288   // Same operation is being done in JVM_BeforeHalt for handling the
3289   // case where the application calls System.exit().
3290   if (DynamicDumpSharedSpaces) {
3291     DynamicArchive::prepare_for_dynamic_dumping();
3292   }
3293 #endif
3294 
3295   EXCEPTION_MARK;
3296   Klass* shutdown_klass =
3297     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3298                                       THREAD);
3299   if (shutdown_klass != NULL) {
3300     // SystemDictionary::resolve_or_null will return null if there was
3301     // an exception.  If we cannot load the Shutdown class, just don't
3302     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3303     // won't be run.  Note that if a shutdown hook was registered,
3304     // the Shutdown class would have already been loaded
3305     // (Runtime.addShutdownHook will load it).
3306     JavaValue result(T_VOID);
3307     JavaCalls::call_static(&result,
3308                            shutdown_klass,
3309                            vmSymbols::shutdown_name(),
3310                            vmSymbols::void_method_signature(),
3311                            THREAD);
3312   }
3313   CLEAR_PENDING_EXCEPTION;
3314 }
3315 
3316 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3317 // the program falls off the end of main(). Another VM exit path is through
3318 // vm_exit() when the program calls System.exit() to return a value or when
3319 // there is a serious error in VM. The two shutdown paths are not exactly
3320 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3321 // and VM_Exit op at VM level.
3322 //
3323 // Shutdown sequence:
3324 //   + Shutdown native memory tracking if it is on
3325 //   + Wait until we are the last non-daemon thread to execute
3326 //     <-- every thing is still working at this moment -->
3327 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3328 //        shutdown hooks
3329 //   + Call before_exit(), prepare for VM exit
3330 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3331 //        currently the only user of this mechanism is File.deleteOnExit())
3332 //      > stop StatSampler, watcher thread,
3333 //        post thread end and vm death events to JVMTI,
3334 //        stop signal thread
3335 //   + Call JavaThread::exit(), it will:
3336 //      > release JNI handle blocks, remove stack guard pages
3337 //      > remove this thread from Threads list
3338 //     <-- no more Java code from this thread after this point -->
3339 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3340 //     the compiler threads at safepoint
3341 //     <-- do not use anything that could get blocked by Safepoint -->
3342 //   + Disable tracing at JNI/JVM barriers
3343 //   + Set _vm_exited flag for threads that are still running native code
3344 //   + Call exit_globals()
3345 //      > deletes tty
3346 //      > deletes PerfMemory resources
3347 //   + Delete this thread
3348 //   + Return to caller
3349 
3350 void Threads::destroy_vm() {
3351   JavaThread* thread = JavaThread::current();
3352 
3353 #ifdef ASSERT
3354   _vm_complete = false;
3355 #endif
3356   // Wait until we are the last non-daemon thread to execute
3357   {
3358     MonitorLocker nu(Threads_lock);
3359     while (Threads::number_of_non_daemon_threads() > 1)
3360       // This wait should make safepoint checks, wait without a timeout.
3361       nu.wait(0);
3362   }
3363 
3364   EventShutdown e;
3365   if (e.should_commit()) {
3366     e.set_reason("No remaining non-daemon Java threads");
3367     e.commit();
3368   }
3369 
3370   // Hang forever on exit if we are reporting an error.
3371   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
3372     os::infinite_sleep();
3373   }
3374   os::wait_for_keypress_at_exit();
3375 
3376   // run Java level shutdown hooks
3377   thread->invoke_shutdown_hooks();
3378 
3379   before_exit(thread);
3380 
3381   thread->exit(true);
3382 
3383   // We are no longer on the main thread list but could still be in a
3384   // secondary list where another thread may try to interact with us.
3385   // So wait until all such interactions are complete before we bring
3386   // the VM to the termination safepoint. Normally this would be done
3387   // using thread->smr_delete() below where we delete the thread, but
3388   // we can't call that after the termination safepoint is active as
3389   // we will deadlock on the Threads_lock. Once all interactions are
3390   // complete it is safe to directly delete the thread at any time.
3391   ThreadsSMRSupport::wait_until_not_protected(thread);
3392 
3393   // Stop VM thread.
3394   {
3395     // 4945125 The vm thread comes to a safepoint during exit.
3396     // GC vm_operations can get caught at the safepoint, and the
3397     // heap is unparseable if they are caught. Grab the Heap_lock
3398     // to prevent this. The GC vm_operations will not be able to
3399     // queue until after the vm thread is dead. After this point,
3400     // we'll never emerge out of the safepoint before the VM exits.
3401     // Assert that the thread is terminated so that acquiring the
3402     // Heap_lock doesn't cause the terminated thread to participate in
3403     // the safepoint protocol.
3404 
3405     assert(thread->is_terminated(), "must be terminated here");
3406     MutexLocker ml(Heap_lock);
3407 
3408     VMThread::wait_for_vm_thread_exit();
3409     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3410     VMThread::destroy();
3411   }
3412 
3413   // Now, all Java threads are gone except daemon threads. Daemon threads
3414   // running Java code or in VM are stopped by the Safepoint. However,
3415   // daemon threads executing native code are still running.  But they
3416   // will be stopped at native=>Java/VM barriers. Note that we can't
3417   // simply kill or suspend them, as it is inherently deadlock-prone.
3418 
3419   VM_Exit::set_vm_exited();
3420 
3421   // Clean up ideal graph printers after the VMThread has started
3422   // the final safepoint which will block all the Compiler threads.
3423   // Note that this Thread has already logically exited so the
3424   // clean_up() function's use of a JavaThreadIteratorWithHandle
3425   // would be a problem except set_vm_exited() has remembered the
3426   // shutdown thread which is granted a policy exception.
3427 #if defined(COMPILER2) && !defined(PRODUCT)
3428   IdealGraphPrinter::clean_up();
3429 #endif
3430 
3431   notify_vm_shutdown();
3432 
3433   // exit_globals() will delete tty
3434   exit_globals();
3435 
3436   // Deleting the shutdown thread here is safe. See comment on
3437   // wait_until_not_protected() above.
3438   delete thread;
3439 
3440 #if INCLUDE_JVMCI
3441   if (JVMCICounterSize > 0) {
3442     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
3443   }
3444 #endif
3445 
3446   LogConfiguration::finalize();
3447 }
3448 
3449 
3450 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3451   if (version == JNI_VERSION_1_1) return JNI_TRUE;
3452   return is_supported_jni_version(version);
3453 }
3454 
3455 
3456 jboolean Threads::is_supported_jni_version(jint version) {
3457   if (version == JNI_VERSION_1_2) return JNI_TRUE;
3458   if (version == JNI_VERSION_1_4) return JNI_TRUE;
3459   if (version == JNI_VERSION_1_6) return JNI_TRUE;
3460   if (version == JNI_VERSION_1_8) return JNI_TRUE;
3461   if (version == JNI_VERSION_9) return JNI_TRUE;
3462   if (version == JNI_VERSION_10) return JNI_TRUE;
3463   return JNI_FALSE;
3464 }
3465 
3466 
3467 void Threads::add(JavaThread* p, bool force_daemon) {
3468   // The threads lock must be owned at this point
3469   assert(Threads_lock->owned_by_self(), "must have threads lock");
3470 
3471   BarrierSet::barrier_set()->on_thread_attach(p);
3472 
3473   // Once a JavaThread is added to the Threads list, smr_delete() has
3474   // to be used to delete it. Otherwise we can just delete it directly.
3475   p->set_on_thread_list();
3476 
3477   _number_of_threads++;
3478   oop threadObj = p->threadObj();
3479   bool daemon = true;
3480   // Bootstrapping problem: threadObj can be null for initial
3481   // JavaThread (or for threads attached via JNI)
3482   if ((!force_daemon) && !is_daemon((threadObj))) {
3483     _number_of_non_daemon_threads++;
3484     daemon = false;
3485   }
3486 
3487   ThreadService::add_thread(p, daemon);
3488 
3489   // Maintain fast thread list
3490   ThreadsSMRSupport::add_thread(p);
3491 
3492   // Increase the ObjectMonitor ceiling for the new thread.
3493   ObjectSynchronizer::inc_in_use_list_ceiling();
3494 
3495   // Possible GC point.
3496   Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
3497 
3498   // Make new thread known to active EscapeBarrier
3499   EscapeBarrier::thread_added(p);
3500 }
3501 
3502 void Threads::remove(JavaThread* p, bool is_daemon) {
3503   // Extra scope needed for Thread_lock, so we can check
3504   // that we do not remove thread without safepoint code notice
3505   { MonitorLocker ml(Threads_lock);
3506 
3507     // BarrierSet state must be destroyed after the last thread transition
3508     // before the thread terminates. Thread transitions result in calls to
3509     // StackWatermarkSet::on_safepoint(), which performs GC processing,
3510     // requiring the GC state to be alive.
3511     BarrierSet::barrier_set()->on_thread_detach(p);
3512 
3513     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
3514 
3515     // Maintain fast thread list
3516     ThreadsSMRSupport::remove_thread(p);
3517 
3518     _number_of_threads--;
3519     if (!is_daemon) {
3520       _number_of_non_daemon_threads--;
3521 
3522       // Only one thread left, do a notify on the Threads_lock so a thread waiting
3523       // on destroy_vm will wake up.
3524       if (number_of_non_daemon_threads() == 1) {
3525         ml.notify_all();
3526       }
3527     }
3528     ThreadService::remove_thread(p, is_daemon);
3529 
3530     // Make sure that safepoint code disregard this thread. This is needed since
3531     // the thread might mess around with locks after this point. This can cause it
3532     // to do callbacks into the safepoint code. However, the safepoint code is not aware
3533     // of this thread since it is removed from the queue.
3534     p->set_terminated(JavaThread::_thread_terminated);
3535 
3536     // Notify threads waiting in EscapeBarriers
3537     EscapeBarrier::thread_removed(p);
3538   } // unlock Threads_lock
3539 
3540   // Reduce the ObjectMonitor ceiling for the exiting thread.
3541   ObjectSynchronizer::dec_in_use_list_ceiling();
3542 
3543   // Since Events::log uses a lock, we grab it outside the Threads_lock
3544   Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
3545 }
3546 
3547 // Operations on the Threads list for GC.  These are not explicitly locked,
3548 // but the garbage collector must provide a safe context for them to run.
3549 // In particular, these things should never be called when the Threads_lock
3550 // is held by some other thread. (Note: the Safepoint abstraction also
3551 // uses the Threads_lock to guarantee this property. It also makes sure that
3552 // all threads gets blocked when exiting or starting).
3553 
3554 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3555   ALL_JAVA_THREADS(p) {
3556     p->oops_do(f, cf);
3557   }
3558   VMThread::vm_thread()->oops_do(f, cf);
3559 }
3560 
3561 void Threads::change_thread_claim_token() {
3562   if (++_thread_claim_token == 0) {
3563     // On overflow of the token counter, there is a risk of future
3564     // collisions between a new global token value and a stale token
3565     // for a thread, because not all iterations visit all threads.
3566     // (Though it's pretty much a theoretical concern for non-trivial
3567     // token counter sizes.)  To deal with the possibility, reset all
3568     // the thread tokens to zero on global token overflow.
3569     struct ResetClaims : public ThreadClosure {
3570       virtual void do_thread(Thread* t) {
3571         t->claim_threads_do(false, 0);
3572       }
3573     } reset_claims;
3574     Threads::threads_do(&reset_claims);
3575     // On overflow, update the global token to non-zero, to
3576     // avoid the special "never claimed" initial thread value.
3577     _thread_claim_token = 1;
3578   }
3579 }
3580 
3581 #ifdef ASSERT
3582 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
3583   const uintx token = t->threads_do_token();
3584   assert(token == expected,
3585          "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
3586          UINTX_FORMAT, kind, p2i(t), token, expected);
3587 }
3588 
3589 void Threads::assert_all_threads_claimed() {
3590   ALL_JAVA_THREADS(p) {
3591     assert_thread_claimed("Thread", p, _thread_claim_token);
3592   }
3593   assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
3594 }
3595 #endif // ASSERT
3596 
3597 class ParallelOopsDoThreadClosure : public ThreadClosure {
3598 private:
3599   OopClosure* _f;
3600   CodeBlobClosure* _cf;
3601 public:
3602   ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
3603   void do_thread(Thread* t) {
3604     t->oops_do(_f, _cf);
3605   }
3606 };
3607 
3608 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
3609   ParallelOopsDoThreadClosure tc(f, cf);
3610   possibly_parallel_threads_do(is_par, &tc);
3611 }
3612 
3613 void Threads::metadata_do(MetadataClosure* f) {
3614   ALL_JAVA_THREADS(p) {
3615     p->metadata_do(f);
3616   }
3617 }
3618 
3619 class ThreadHandlesClosure : public ThreadClosure {
3620   void (*_f)(Metadata*);
3621  public:
3622   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
3623   virtual void do_thread(Thread* thread) {
3624     thread->metadata_handles_do(_f);
3625   }
3626 };
3627 
3628 void Threads::metadata_handles_do(void f(Metadata*)) {
3629   // Only walk the Handles in Thread.
3630   ThreadHandlesClosure handles_closure(f);
3631   threads_do(&handles_closure);
3632 }
3633 
3634 // Get count Java threads that are waiting to enter the specified monitor.
3635 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
3636                                                          int count,
3637                                                          address monitor) {
3638   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3639 
3640   int i = 0;
3641   for (JavaThread* p : *t_list) {
3642     if (!p->can_call_java()) continue;
3643 
3644     // The first stage of async deflation does not affect any field
3645     // used by this comparison so the ObjectMonitor* is usable here.
3646     address pending = (address)p->current_pending_monitor();
3647     if (pending == monitor) {             // found a match
3648       if (i < count) result->append(p);   // save the first count matches
3649       i++;
3650     }
3651   }
3652 
3653   return result;
3654 }
3655 
3656 
3657 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
3658                                                       address owner) {
3659   // NULL owner means not locked so we can skip the search
3660   if (owner == NULL) return NULL;
3661 
3662   for (JavaThread* p : *t_list) {
3663     // first, see if owner is the address of a Java thread
3664     if (owner == (address)p) return p;
3665   }
3666 
3667   // Cannot assert on lack of success here since this function may be
3668   // used by code that is trying to report useful problem information
3669   // like deadlock detection.
3670   if (UseHeavyMonitors) return NULL;
3671 
3672   // If we didn't find a matching Java thread and we didn't force use of
3673   // heavyweight monitors, then the owner is the stack address of the
3674   // Lock Word in the owning Java thread's stack.
3675   //
3676   JavaThread* the_owner = NULL;
3677   for (JavaThread* q : *t_list) {
3678     if (q->is_lock_owned(owner)) {
3679       the_owner = q;
3680       break;
3681     }
3682   }
3683 
3684   // cannot assert on lack of success here; see above comment
3685   return the_owner;
3686 }
3687 
3688 class PrintOnClosure : public ThreadClosure {
3689 private:
3690   outputStream* _st;
3691 
3692 public:
3693   PrintOnClosure(outputStream* st) :
3694       _st(st) {}
3695 
3696   virtual void do_thread(Thread* thread) {
3697     if (thread != NULL) {
3698       thread->print_on(_st);
3699       _st->cr();
3700     }
3701   }
3702 };
3703 
3704 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3705 void Threads::print_on(outputStream* st, bool print_stacks,
3706                        bool internal_format, bool print_concurrent_locks,
3707                        bool print_extended_info) {
3708   char buf[32];
3709   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
3710 
3711   st->print_cr("Full thread dump %s (%s %s):",
3712                VM_Version::vm_name(),
3713                VM_Version::vm_release(),
3714                VM_Version::vm_info_string());
3715   st->cr();
3716 
3717 #if INCLUDE_SERVICES
3718   // Dump concurrent locks
3719   ConcurrentLocksDump concurrent_locks;
3720   if (print_concurrent_locks) {
3721     concurrent_locks.dump_at_safepoint();
3722   }
3723 #endif // INCLUDE_SERVICES
3724 
3725   ThreadsSMRSupport::print_info_on(st);
3726   st->cr();
3727 
3728   ALL_JAVA_THREADS(p) {
3729     ResourceMark rm;
3730     p->print_on(st, print_extended_info);
3731     if (print_stacks) {
3732       if (internal_format) {
3733         p->trace_stack();
3734       } else {
3735         p->print_stack_on(st);
3736       }
3737     }
3738     st->cr();
3739 #if INCLUDE_SERVICES
3740     if (print_concurrent_locks) {
3741       concurrent_locks.print_locks_on(p, st);
3742     }
3743 #endif // INCLUDE_SERVICES
3744   }
3745 
3746   PrintOnClosure cl(st);
3747   cl.do_thread(VMThread::vm_thread());
3748   Universe::heap()->gc_threads_do(&cl);
3749   if (StringDedup::is_enabled()) {
3750     StringDedup::threads_do(&cl);
3751   }
3752   cl.do_thread(WatcherThread::watcher_thread());
3753   cl.do_thread(AsyncLogWriter::instance());
3754 
3755   st->flush();
3756 }
3757 
3758 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
3759                              int buflen, bool* found_current) {
3760   if (this_thread != NULL) {
3761     bool is_current = (current == this_thread);
3762     *found_current = *found_current || is_current;
3763     st->print("%s", is_current ? "=>" : "  ");
3764 
3765     st->print(PTR_FORMAT, p2i(this_thread));
3766     st->print(" ");
3767     this_thread->print_on_error(st, buf, buflen);
3768     st->cr();
3769   }
3770 }
3771 
3772 class PrintOnErrorClosure : public ThreadClosure {
3773   outputStream* _st;
3774   Thread* _current;
3775   char* _buf;
3776   int _buflen;
3777   bool* _found_current;
3778  public:
3779   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
3780                       int buflen, bool* found_current) :
3781    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
3782 
3783   virtual void do_thread(Thread* thread) {
3784     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
3785   }
3786 };
3787 
3788 // Threads::print_on_error() is called by fatal error handler. It's possible
3789 // that VM is not at safepoint and/or current thread is inside signal handler.
3790 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3791 // memory (even in resource area), it might deadlock the error handler.
3792 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
3793                              int buflen) {
3794   ThreadsSMRSupport::print_info_on(st);
3795   st->cr();
3796 
3797   bool found_current = false;
3798   st->print_cr("Java Threads: ( => current thread )");
3799   ALL_JAVA_THREADS(thread) {
3800     print_on_error(thread, st, current, buf, buflen, &found_current);
3801   }
3802   st->cr();
3803 
3804   st->print_cr("Other Threads:");
3805   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
3806   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
3807   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
3808 
3809   if (Universe::heap() != NULL) {
3810     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3811     Universe::heap()->gc_threads_do(&print_closure);
3812   }
3813 
3814   if (StringDedup::is_enabled()) {
3815     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3816     StringDedup::threads_do(&print_closure);
3817   }
3818 
3819   if (!found_current) {
3820     st->cr();
3821     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
3822     current->print_on_error(st, buf, buflen);
3823     st->cr();
3824   }
3825   st->cr();
3826 
3827   st->print_cr("Threads with active compile tasks:");
3828   print_threads_compiling(st, buf, buflen);
3829 }
3830 
3831 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
3832   ALL_JAVA_THREADS(thread) {
3833     if (thread->is_Compiler_thread()) {
3834       CompilerThread* ct = (CompilerThread*) thread;
3835 
3836       // Keep task in local variable for NULL check.
3837       // ct->_task might be set to NULL by concurring compiler thread
3838       // because it completed the compilation. The task is never freed,
3839       // though, just returned to a free list.
3840       CompileTask* task = ct->task();
3841       if (task != NULL) {
3842         thread->print_name_on_error(st, buf, buflen);
3843         st->print("  ");
3844         task->print(st, NULL, short_form, true);
3845       }
3846     }
3847   }
3848 }
3849 
3850 
3851 // Ad-hoc mutual exclusion primitives: SpinLock
3852 //
3853 // We employ SpinLocks _only for low-contention, fixed-length
3854 // short-duration critical sections where we're concerned
3855 // about native mutex_t or HotSpot Mutex:: latency.
3856 //
3857 // TODO-FIXME: ListLock should be of type SpinLock.
3858 // We should make this a 1st-class type, integrated into the lock
3859 // hierarchy as leaf-locks.  Critically, the SpinLock structure
3860 // should have sufficient padding to avoid false-sharing and excessive
3861 // cache-coherency traffic.
3862 
3863 
3864 typedef volatile int SpinLockT;
3865 
3866 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
3867   if (Atomic::cmpxchg(adr, 0, 1) == 0) {
3868     return;   // normal fast-path return
3869   }
3870 
3871   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
3872   int ctr = 0;
3873   int Yields = 0;
3874   for (;;) {
3875     while (*adr != 0) {
3876       ++ctr;
3877       if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
3878         if (Yields > 5) {
3879           os::naked_short_sleep(1);
3880         } else {
3881           os::naked_yield();
3882           ++Yields;
3883         }
3884       } else {
3885         SpinPause();
3886       }
3887     }
3888     if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
3889   }
3890 }
3891 
3892 void Thread::SpinRelease(volatile int * adr) {
3893   assert(*adr != 0, "invariant");
3894   OrderAccess::fence();      // guarantee at least release consistency.
3895   // Roach-motel semantics.
3896   // It's safe if subsequent LDs and STs float "up" into the critical section,
3897   // but prior LDs and STs within the critical section can't be allowed
3898   // to reorder or float past the ST that releases the lock.
3899   // Loads and stores in the critical section - which appear in program
3900   // order before the store that releases the lock - must also appear
3901   // before the store that releases the lock in memory visibility order.
3902   // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
3903   // the ST of 0 into the lock-word which releases the lock, so fence
3904   // more than covers this on all platforms.
3905   *adr = 0;
3906 }
3907 
3908 
3909 void Threads::verify() {
3910   ALL_JAVA_THREADS(p) {
3911     p->verify();
3912   }
3913   VMThread* thread = VMThread::vm_thread();
3914   if (thread != NULL) thread->verify();
3915 }
3916 
3917 #ifndef PRODUCT
3918 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
3919    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
3920 }
3921 #endif
3922 
3923 // Helper function to create the java.lang.Thread object for a
3924 // VM-internal thread. The thread will have the given name, be
3925 // part of the System ThreadGroup and if is_visible is true will be
3926 // discoverable via the system ThreadGroup.
3927 Handle JavaThread::create_system_thread_object(const char* name,
3928                                                bool is_visible, TRAPS) {
3929   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
3930 
3931   // Initialize thread_oop to put it into the system threadGroup.
3932   // This is done by calling the Thread(ThreadGroup tg, String name)
3933   // constructor, which adds the new thread to the group as an unstarted
3934   // thread.
3935   Handle thread_group(THREAD, Universe::system_thread_group());
3936   Handle thread_oop =
3937     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
3938                                       vmSymbols::threadgroup_string_void_signature(),
3939                                       thread_group,
3940                                       string,
3941                                       CHECK_NH);
3942 
3943   // If the Thread is intended to be visible then we have to mimic what
3944   // Thread.start() would do, by adding it to its ThreadGroup: tg.add(t).
3945   if (is_visible) {
3946     Klass* group = vmClasses::ThreadGroup_klass();
3947     JavaValue result(T_VOID);
3948     JavaCalls::call_special(&result,
3949                             thread_group,
3950                             group,
3951                             vmSymbols::add_method_name(),
3952                             vmSymbols::thread_void_signature(),
3953                             thread_oop,
3954                             CHECK_NH);
3955   }
3956 
3957   return thread_oop;
3958 }
3959 
3960 // Starts the target JavaThread as a daemon of the given priority, and
3961 // bound to the given java.lang.Thread instance.
3962 // The Threads_lock is held for the duration.
3963 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
3964                                        Handle thread_oop, ThreadPriority prio) {
3965 
3966   assert(target->osthread() != NULL, "target thread is not properly initialized");
3967 
3968   MutexLocker mu(current, Threads_lock);
3969 
3970   // Initialize the fields of the thread_oop first.
3971 
3972   java_lang_Thread::set_thread(thread_oop(), target); // isAlive == true now
3973 
3974   if (prio != NoPriority) {
3975     java_lang_Thread::set_priority(thread_oop(), prio);
3976     // Note: we don't call os::set_priority here. Possibly we should,
3977     // else all threads should call it themselves when they first run.
3978   }
3979 
3980   java_lang_Thread::set_daemon(thread_oop());
3981 
3982   // Now bind the thread_oop to the target JavaThread.
3983   target->set_threadObj(thread_oop());
3984 
3985   Threads::add(target); // target is now visible for safepoint/handshake
3986   Thread::start(target);
3987 }
3988 
3989 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
3990   // At this point it may be possible that no osthread was created for the
3991   // JavaThread due to lack of resources. However, since this must work
3992   // for critical system threads just check and abort if this fails.
3993   if (thread->osthread() == nullptr) {
3994     // This isn't really an OOM condition, but historically this is what
3995     // we report.
3996     vm_exit_during_initialization("java.lang.OutOfMemoryError",
3997                                   os::native_thread_creation_failed_msg());
3998   }
3999 }